Warn user when build fingerprints differ.

We're now shipping devices with several partitions which may end up
mismatched, causing subtle runtime issues.  To help manufacturers and
users catch this case, show wanring when we detected mismatched
fingerprints.

Bug: 18357469
Change-Id: I897d7ee8cbf3b8042d3d7d282afab277d242ed3f
4 files changed