Replace the sqlalchemy engine and session management with an oslo.db
facade. This does the work transparently and fixes connection
mismanagement.
The changes involve:
- modifying the sqlalchemy session script to use oslo_db functions
- adding the oslo_db engine configuration parameters
- tweaking the faked tests to pass*
* the faked tests are sensitive to sleep calls and oslo_db uses a
sleep(0) hack which was causing issues. The coverage of the tests was
not affected.
Implements: blueprint move-to-oslo-db
Change-Id: I59f1fc0fe1551b9a815a51e6a620fabf060b013f
27a4e2c650