Removed TRYSERVER_ROOT since this is not used anymore

Instead PROJECT property is used by Rietveld to set patch_project, which is then
mapped to correct path in the recipe.

R=machenbach@chromium.org

Review URL: https://codereview.chromium.org/878573003

Cr-Commit-Position: refs/heads/master@{#26304}

codereview.settings

@@ -4,6 +4,5 @@ VIEW_VC: https://chromium.googlesource.com/v8/v8/+/
 STATUS: http://v8-status.appspot.com/status
 TRY_ON_UPLOAD: False
 TRYSERVER_SVN_URL: svn://svn.chromium.org/chrome-try-v8
-TRYSERVER_ROOT: v8
 PROJECT: v8
 PENDING_REF_PREFIX: refs/pending/