Fixes to get unit tests to compile

There are 2 CI failures that started showing up at the same time:

1) sdbusplus recenty had a commit that started checking the return code
   on sd_bus_add_object_vtable and now 2 tests are getting those fails
   in CI, so used the mocked bus objects instead.

2) pel_values_test.cpp fails with:
    Expected equality of these values:
       "cec_service_network"
         Which is: 0x563efae570fc
       std::get<registryNamePos>(*s)
         Which is: 0x563efae57a64
   because it is using EXPECT_EQ to compare to char* values instead of
   EXPECT_STREQ.  I'm not sure what changed that uncovered this.

Fix them both at the same time as CI won't pass when doing them
separately because of the other error.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I937bd6d6965be5c8aab26f6c539cf30537439e0b
diff --git a/test/extensions_test.cpp b/test/extensions_test.cpp
index d210115..6dfe9be 100644
--- a/test/extensions_test.cpp
+++ b/test/extensions_test.cpp
@@ -1,6 +1,8 @@
 #include "elog_entry.hpp"
 #include "extensions.hpp"
 
+#include <sdbusplus/test/sdbus_mock.hpp>
+
 #include <gtest/gtest.h>
 
 using namespace phosphor::logging;
@@ -63,7 +65,8 @@
 
 TEST(ExtensionsTest, FunctionCallTest)
 {
-    auto bus = sdbusplus::bus::new_default();
+    sdbusplus::SdBusMock sdbusMock;
+    sdbusplus::bus::bus bus = sdbusplus::get_mocked_new(&sdbusMock);
     internal::Manager manager(bus, "testpath");
 
     EXPECT_EQ(Extensions::getStartupFunctions().size(), 2);