Enable -Wself-assign-memvar for Mesa, merge upstream fix for the one violation

BUG=none
TEST=none


Review URL: https://chromiumcodereview.appspot.com/10808045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src/third_party/mesa/MesaLib@147658 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed