Move db.sql.util to db.util

Now that sqlalchemy is providing the database abstractions, there is no
need to hide everything in db.sql. sub-modules. It complicates the code
and provides a futher layer of indirection.

Move the db.sql.util.py to db.util.py and adapt the importers.

mediagoblin/gmg_commands/dbupdate.py

@@ -19,7 +19,7 @@ import logging
 from sqlalchemy.orm import sessionmaker
 
 from mediagoblin.db.open import setup_connection_and_db_from_config
-from mediagoblin.db.sql.util import MigrationManager
+from mediagoblin.db.util import MigrationManager
 from mediagoblin.init import setup_global_and_app_config
 from mediagoblin.tools.common import import_component