Merge "Only purge sound models that violate the new primary key constraint if...

Merge "Only purge sound models that violate the new primary key constraint if they don't contain identical data." into nyc-mr1-dev am: 23655af5 am: 1696610b
am: 1ff7f782

Change-Id: Iae8f6d22b7f6b2d81d7aebb5d22e360a41b9ede0