Run storage unit tests in pooled context

Enable storage unit tests for pooled context. This patch adds check for
pooling in test config in test initialization and creates appropriate
wrappers.

Also changes to sqlalchemy pooling controllers were made: in pooled
context project cannot be None due to constraint in database.

Change-Id: I59a663cef5b761e9470b8870d07cea03f5dac98b
Merge "Run storage unit tests in pooled context"