Remove unused function and argument

I removed the unused function and (function)argument in code

Change-Id: Ib7afa5d868c3c7769f53e45c270850e4c3370f86

watcher/db/sqlalchemy/migration.py

@@ -32,7 +32,7 @@ def _alembic_config():
     return config
 
 
-def version(config=None, engine=None):
+def version(engine=None):
     """Current database version.
 
     :returns: Database version