NCBC-675: Fixed servers with FQDN not properly resolving.

If a bucket configuration returned from a Couchbase cluster contains a
fully qualified domain name instead of an IP address,
CouchbaseConfigContext will not properly resolve the endpoint, resulting
in a null KeyMapper. Upon any operation that requires the KeyMapper, the
Couchbase .Net client will throw a NullReferenceException.

Change-Id: I33a240f956492deedbca0b0015ead3c47583bb21
Reviewed-on: http://review.couchbase.org/41984
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>
Tested-by: Jeffry Morris <jeffrymorris@gmail.com>