Restore 'root' build property temporarily
Restore 'root' build property temporarily

The 'root' property may be assigned from TRYSERVER_ROOT property in codereview.settings for projects that use git try. Follow up CL will parse codereview.settings in the recipe. After that 'root' can be removed again. Additionally, we will be able to remove hard-coded dict (patch_project_roots) and move configuration into projects themselves (codereview.settings).


BUG=4150
R=kjellander@webrtc.org,iannucci@chromium.org

Review URL: https://codereview.chromium.org/838913004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@293603 0039d316-1c4b-4281-b951-d872f2087c98

luci/recipes-py,luci/recipes-py,shishkander/recipes-py,shishkander/recipes-py