Migrate to Oslo DB 96d1f887dda Part 3

Oslo version 96d1f887dda21b43ba4376187f31953dee6f5273

This commit just migrates Heat to new db related code from Oslo

Partially implements blueprint oslo-db-support

Change-Id: Ib0de40a70857fb3e029a2282f06746269a628c71
Merge "Migrate to Oslo DB 96d1f887dda Part 3"