Removed `#rabbit_server` method

This was a mistake on my part adding this method.  The rabbit-host
directive takes a host, not a host and port.  We are going to lock
0.3.0 version of this library Monday, and not add any minor features.
Wanted to delete this confusing method, before we lock this version
down.

Change-Id: Ibc48fc267f2b0a1ee83963f49818edbd67adaca2