Remove sql.Base

With the change to use oslo's db.sqlalchemy.sessions, the
sql.Base class isn't doing enough to justify its continued
existence.

This change removes sql.Base.

Part of bp use-common-oslo-db-code

Change-Id: I2fec97187bdca920757585994810f6a8065be4c4
Fix assertEqual arguments order

assertEqual method's arguments should be in
('expected', 'actual') order.

This patch fixes this problem of the following modules:

* keystone/tests/test_auth.py
* keystone/tests/test_sizelimit.py
* keystone/tests/test_ssl.py

Partially Close-bug: #1277104

Change-Id: Ic1bd330544fa954cd683ece75b953259e70440fe
Merge "Fix assertEqual arguments order"