Merge "Remove pre-N db after successful migration" into nyc-dev
am: cdb5fcf7b8

* commit 'cdb5fcf7b81de81793995097b017c001be2a4264':
  Remove pre-N db after successful migration

Change-Id: I3c45a3bc5bf26fccf5fd8b09e0d8e1989b8832a0