test: fixing variable names for test suite inside configure.ac.

Both variables for gcov and oom have wrong names inside configure.ac.
For this reason, the Test Suite configuration is not showing the current
configuration.

Before patching:
configure:    windres: no
configure:
configure: Test suite
configure:
configure:          Coverage:
configure:         Alloc OOM:
configure:
configure: Miscellaneous

After patching (using --enable-test-coverage and --enable-test-oom):
configure:    windres: no
configure:
configure: Test suite
configure:
configure:          Coverage: yes
configure:         Alloc OOM: yes
configure:
configure: Miscellaneous
Signed-off-by: NJulio Faracco <jcfaracco@gmail.com>

configure.ac

@@ -1005,8 +1005,8 @@ LIBVIRT_WIN_RESULT_WINDRES
 AC_MSG_NOTICE([])
 AC_MSG_NOTICE([Test suite])
 AC_MSG_NOTICE([])
-AC_MSG_NOTICE([         Coverage: $enable_coverage])
-AC_MSG_NOTICE([        Alloc OOM: $enable_oom])
+AC_MSG_NOTICE([         Coverage: $enable_test_coverage])
+AC_MSG_NOTICE([        Alloc OOM: $enable_test_oom])
 AC_MSG_NOTICE([])
 AC_MSG_NOTICE([Miscellaneous])
 AC_MSG_NOTICE([])