Handle case where chromite dir is missing.

Right now cbuildbot uses cros_sdk before we've even updated the Chrome
OS source code. This can cause issues if the old version of cros_sdk
is missing or corrupted.

Fortunately, we already unmount the directories ourselves, so it is
safe for us to just rm -rf the dir.

BUG=chromium:258167
TEST=Run trybot run on machine with missing chromite dir.
TEST=Run a bunch of trybot runs including stop build runs.

Change-Id: I2b7d87588dafbac937e114225091c877702bd62c
Reviewed-on: https://gerrit.chromium.org/gerrit/61373
Reviewed-by: Matt Tennant <mtennant@chromium.org>
Commit-Queue: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
1 file changed