LeveldbValueStore: Deleting db when open fails due to corruption.

Corrupted databases would never be deleted. This change will delete
the leveldb database iff an open attempt fails as a result of
corruption.

This class is currently used by the Extensions component in Chrome.

BUG=549177

Review URL: https://codereview.chromium.org/1428843002

Cr-Commit-Position: refs/heads/master@{#358722}
3 files changed