Fixed PHP-874: When checking the node type, we should drop unknown membe...

...rs right away

If we don't drop the connection here we will continue and try to
authenticate - which will attempt to take a lock on the server.. which
will go so well during initial sync and index creations for example.

This was "only" a problem when using authentication, as even if we had
the connection around normally, we don't have read preferences that
would use it so no harm no faul, just a silly thing to keep around