Fix duplicating of SQL queries in logs

Remove setting and passing echo parameter to create_engine()
function and replace it with configuring log level directly on
logger sqlalchemy.engine (this prevents adding of multiple
handlers writing to stderr to the root logger).

Change-Id: I799341a347cfcacdd27c70b91ed9b9e3cc70727f
Closes-Bug: #1278860
Merge "Fix duplicating of SQL queries in logs"