tests: Quick fix for googletest

The test cases need to be linked agaist not only -lgmock_main and
-lgmock but also against -lgtest to pull in all of the needed symbols.
Specifically the build was missing the ::testing::Test symbol.
Googletest changed the way they link their libraries in the newer
version. Instead of including all the objects for libgtest inside of
libgmock, they have libgmock append a DT_NEEDED on libgtest. This is
breaking out linking process. Since we are using googletest
functionality, link against libgtest as expected.

Tested:
    Unit tests build and pass again.

Change-Id: I56be07eec7d89e0042edba35b64ce1d94f85c4b4
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/Makefile.am b/test/Makefile.am
index 5311f9f..ff56179 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -14,6 +14,6 @@
 
 utest_CXXFLAGS = $(PTHREAD_CFLAGS)
 
-utest_LDFLAGS = -lgmock_main \
+utest_LDFLAGS = -lgtest -lgmock -lgmock_main \
                 $(PTHREAD_LIBS) \
                 $(OESDK_TESTCASE_FLAGS)