fix unused variable warning

The object code relies on the side effects of the creation of the d
variable.  Cast the var as a (void) to disable the warning:

.../libchromeos/chromeos/glib/object_unittest.cc: In member function 'virtual void ScopedErrorTest_All_Test::TestBody()':
.../libchromeos/chromeos/glib/object_unittest.cc:86:13: warning: unused variable 'd' [-Wunused-variable]
   ::GError* d = ::g_error_new(::g_quark_from_static_string("error"), -1,
             ^
At global scope:

BUG=None
TEST=`FEATURES=test emerge-x86-alex platform2` passes & doesn't warn about this
TEST=`FEATURES=test emerge-daisy platform2` passes & doesn't warn about this

Change-Id: I7120b54a992da7c67842a73de433f41b395e47d1
Reviewed-on: https://chromium-review.googlesource.com/180297
Reviewed-by: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
1 file changed