Skia: replace build5-a3 with vm255-m3
Skia: replace build5-a3 with vm255-m3

This should fix the broken "Mac Builder"

TBR=rmistry
BUG=chromium:513325,skia:4107

Review URL: https://codereview.chromium.org/1254813004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@296104 0039d316-1c4b-4281-b951-d872f2087c98

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