Link to buildbot status page:
https://uberchromegw.corp.google.com/i/tryserver.chromium.perf/buildslaves/build183-b4


bot_update fails with:


Traceback (most recent call last):
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\git_cache.py", line 801, in <module>
    sys.exit(main(sys.argv[1:]))
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\git_cache.py", line 796, in main
    return dispatcher.execute(OptionParser(), argv)
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\subcommand.py", line 252, in execute
    return command(parser, args[1:])
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\git_cache.py", line 669, in CMDpopulate
    mirror.populate(**kwargs)
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\git_cache.py", line 512, in populate
    self._fetch(tempdir or self.mirror_path, verbose, depth)
  File "C:\b\rr\tmppxz5uc\rw\checkout\scripts\slave\.recipe_deps\depot_tools\git_cache.py", line 487, in _fetch
    raise ClobberNeeded()  # Corrupted cache.
__main__.ClobberNeeded
===Failed in 0.5 mins===