Example: https://uberchromegw.corp.google.com/i/chromiumos/builders/chromiumos-sdk/builds/8545

Builds are failing repeatedly in the SyncChrome stage with multiple instances of:

git_cache.LockError: /b/git-cache/chromium.googlesource.com-chromium-src is already locked
WARNING: Chrome checkout appears corrupt. Clobbering.


Note that this started happening after the waterfall restart around 9:55AM yesterday (2/15).
This build was interrupted due to the restart: https://uberchromegw.corp.google.com/i/chromiumos/builders/chromiumos-sdk/builds/8544
Maybe the restart left the git-cache in a bad and/or locked state. This run was in the middle of SyncChrome stage when it was interrupted.