GTTF: Make update_scripts failures not fail the build, just warn
GTTF: Make update_scripts failures not fail the build, just warn

BUG=310396

Review URL: https://codereview.chromium.org/138873004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@245306 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build