mongo-client: Bail out early from mongo_connection if it is failing.
mongo-client: Bail out early from mongo_connection if it is failing.

Instead of trying to fiddle with the file descriptior, bail out early,
if we already know that the connection did not succeed.

This way we do not needlessly clobber errno, and the calling
application can therefore use it.

algernon/libmongo-client,algernon/libmongo-client,algernon/libmongo-client