Deprecate std::filesystem namespace include

Clang-tidy is complaining about our using fs = ... directives.  These
were originally added to handle boost::filesystem vs
std::experimental::filesystem vs std::filesystem between the various
compilers.  Now that we're all on std::filesystem, this redefinition can
be removed.

```
ChassisIntrusionSensor.hpp:11:11: error: namespace alias decl 'fs' is unused [misc-unused-alias-decls,-warnings-as-errors]
   11 | namespace fs = std::filesystem;
```

Tested: code compiles

Change-Id: If4b968ff9cceb4038f526321d3c7c11563ffbce9
Signed-off-by: Ed Tanous <etanous@nvidia.com>
diff --git a/src/tests/test_Utils.cpp b/src/tests/test_Utils.cpp
index 8192475..3db6727 100644
--- a/src/tests/test_Utils.cpp
+++ b/src/tests/test_Utils.cpp
@@ -13,13 +13,12 @@
 
 #include <gtest/gtest.h>
 
-namespace fs = std::filesystem;
 class TestUtils : public testing::Test
 {
   public:
     std::string testDir;
-    fs::path hwmonDir;
-    fs::path peciDir;
+    std::filesystem::path hwmonDir;
+    std::filesystem::path peciDir;
     TestUtils()
     {
         // Create test environment
@@ -30,10 +29,10 @@
         {
             throw std::bad_alloc();
         }
-        hwmonDir = fs::path(testDir) / "hwmon";
-        fs::create_directory(hwmonDir);
+        hwmonDir = std::filesystem::path(testDir) / "hwmon";
+        std::filesystem::create_directory(hwmonDir);
         auto hwmon10 = hwmonDir / "hwmon10";
-        fs::create_directory(hwmonDir / "hwmon10");
+        std::filesystem::create_directory(hwmonDir / "hwmon10");
         {
             std::ofstream temp1Input{hwmon10 / "temp1_input"};
             std::ofstream temp1Min{hwmon10 / "temp1_min"};
@@ -45,7 +44,7 @@
 
     ~TestUtils() override
     {
-        fs::remove_all(testDir);
+        std::filesystem::remove_all(testDir);
     }
 
     TestUtils(const TestUtils&) = delete;
@@ -55,10 +54,10 @@
 
     void createPECIDir()
     {
-        peciDir = fs::path(testDir) / "peci";
+        peciDir = std::filesystem::path(testDir) / "peci";
         auto peci0 = peciDir /
                      "peci-0/device/0-30/peci-cputemp.0/hwmon/hwmon25";
-        fs::create_directories(peci0);
+        std::filesystem::create_directories(peci0);
         {
             std::ofstream temp0Input{peci0 / "temp0_input"};
             std::ofstream temp1Input{peci0 / "temp1_input"};
@@ -66,14 +65,17 @@
             std::ofstream name{peci0 / "name"};
         }
         auto devDir = peciDir / "peci-0/peci_dev/peci-0";
-        fs::create_directories(devDir);
-        fs::create_directory_symlink("../../../peci-0", devDir / "device");
-        fs::create_directory_symlink("device/0-30", peciDir / "peci-0/0-30");
+        std::filesystem::create_directories(devDir);
+        std::filesystem::create_directory_symlink("../../../peci-0",
+                                                  devDir / "device");
+        std::filesystem::create_directory_symlink("device/0-30",
+                                                  peciDir / "peci-0/0-30");
 
         // Let's keep this for debugging purpose
-        for (auto p = fs::recursive_directory_iterator(
-                 peciDir, fs::directory_options::follow_directory_symlink);
-             p != fs::recursive_directory_iterator(); ++p)
+        for (auto p = std::filesystem::recursive_directory_iterator(
+                 peciDir,
+                 std::filesystem::directory_options::follow_directory_symlink);
+             p != std::filesystem::recursive_directory_iterator(); ++p)
         {
             std::string path = p->path().string();
             std::cerr << path << "\n";
@@ -87,7 +89,7 @@
 
 TEST_F(TestUtils, findFiles_non_exist)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret = findFiles("non-exist", "", foundPaths);
 
     EXPECT_FALSE(ret);
@@ -96,7 +98,7 @@
 
 TEST_F(TestUtils, findFiles_in_hwmon_no_match)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret = findFiles(hwmonDir, R"(in\d+_input)", foundPaths);
 
     EXPECT_TRUE(ret);
@@ -105,7 +107,7 @@
 
 TEST_F(TestUtils, findFiles_in_hwmon_match)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret = findFiles(hwmonDir, R"(temp\d+_input)", foundPaths);
 
     EXPECT_TRUE(ret);
@@ -114,7 +116,7 @@
 
 TEST_F(TestUtils, findFiles_in_peci_no_match)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret =
         findFiles(peciDir, R"(peci-\d+/\d+-.+/peci-.+/hwmon/hwmon\d+/aaa$)",
                   foundPaths, 6);
@@ -125,7 +127,7 @@
 
 TEST_F(TestUtils, findFiles_in_peci_match)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret =
         findFiles(peciDir, R"(peci-\d+/\d+-.+/peci-.+/hwmon/hwmon\d+/name$)",
                   foundPaths, 6);
@@ -144,7 +146,7 @@
 TEST_F(TestUtils, findFiles_hwmonPath_end_with_slash)
 {
     std::string p = hwmonDir.string() + "/";
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret = findFiles(p, R"(temp\d+_input)", foundPaths);
 
     EXPECT_TRUE(ret);
@@ -154,7 +156,7 @@
 TEST_F(TestUtils, findFiles_peciPath_end_with_slash)
 {
     std::string p = peciDir.string() + "/";
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret =
         findFiles(p, R"(peci-\d+/\d+-.+/peci-.+/hwmon/hwmon\d+/temp\d+_input)",
                   foundPaths, 6);
@@ -165,7 +167,7 @@
 
 TEST_F(TestUtils, findFiles_in_sub_peci_match)
 {
-    std::vector<fs::path> foundPaths;
+    std::vector<std::filesystem::path> foundPaths;
     auto ret =
         findFiles(peciDir / "peci-0", R"(\d+-.+/peci-.+/hwmon/hwmon\d+/name$)",
                   foundPaths, 5);