Move all variant usage to std

This just a style change, remove variant_ns
in favor of std.

Tested-by: it built

Change-Id: Id5a075e8b73a7724cbc5153fb7dfcf369e79c483
Signed-off-by: James Feist <james.feist@linux.intel.com>
diff --git a/test/dbus_passive_unittest.cpp b/test/dbus_passive_unittest.cpp
index 52126cf..81238a5 100644
--- a/test/dbus_passive_unittest.cpp
+++ b/test/dbus_passive_unittest.cpp
@@ -3,6 +3,7 @@
 
 #include <sdbusplus/test/sdbus_mock.hpp>
 #include <string>
+#include <variant>
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -138,7 +139,7 @@
     const char* Value = "Value";
     int64_t xValue = 10000;
     const char* intf = "xyz.openbmc_project.Sensor.Value";
-    // string, std::map<std::string, sdbusplus::message::variant<int64_t>>
+    // string, std::map<std::string, std::variant<int64_t>>
     // msg.read(msgSensor, msgData);
 
     EXPECT_CALL(sdbus_mock, sd_bus_message_read_basic(IsNull(), 's', NotNull()))
@@ -208,7 +209,7 @@
     const char* Scale = "Scale";
     int64_t xScale = -6;
     const char* intf = "xyz.openbmc_project.Sensor.Value";
-    // string, std::map<std::string, sdbusplus::message::variant<int64_t>>
+    // string, std::map<std::string, std::variant<int64_t>>
     // msg.read(msgSensor, msgData);
 
     EXPECT_CALL(sdbus_mock, sd_bus_message_read_basic(IsNull(), 's', NotNull()))