Added silly logging to warn that user or password is not provided to connection

Added a log message if the user does not provide a 'user' or 'password' to the connection.
This will only show up if sails is run under log mode 'silly'.

This is needed because me and other's https://github.com/balderdashy/sails/issues/2448#issuecomment-65905122 seems to have had problem with local mongoDb auth understanding/finding out there were a typo.