Skip buildbot runs if a specific substring exists in a CL's commit message.
Skip buildbot runs if a specific substring exists in a CL's commit message.

Created to fix the feature request http://code.google.com/p/skia/issues/detail?id=1089 : buildbot: Skip buildbot runs if a CL contains a specific substring.
Review URL: https://codereview.appspot.com/7204056

git-svn-id: 32fc27f4dcfb6c0385cd9719852b95fe6680452d@7440 2bbb7eff-a529-9590-31e7-b0007b416f81

google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot