MB-9847 Don't bother user when port terminates normally.

Change-Id: I366a386a13e53e076f6a78073113c5c513d19d3d
Reviewed-on: http://review.couchbase.org/33015
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Artem Stemkovski <artem@couchbase.com>