Add code from Oslo DB 96d1f887dda Part 2

Oslo version 96d1f887dda21b43ba4376187f31953dee6f5273

This commit just adds new db related code from Oslo
into Heat without additional changes

Partially implements blueprint oslo-db-support

Change-Id: I97515beaf0713f409405bdc27590e216f6ed1937
Merge "Add code from Oslo DB 96d1f887dda Part 2"