0.9.x - fix for #338

This definintely fixes the "databaseName must be a string" error, but it may have some unintended consequences somewhere. 

Basically, somehow the self.query object has a key 'config' which is undefined, and it overwrites collection.config, which causes the "databaseName must be a string" error when the connection is being established. 

I think I should be setting that somewhere else (on the self.query object maybe?) But I could not trace where I should put it. Help will be appreciated here.