Allow the monitor interface to be defined.
Allow the monitor interface to be defined.

Don't use the detected interface if CEPH_ETH is defined.  Detected based
on the amount of traffic over the interface is not always the
wanted behaviour.

Signed-off-by: Mike Terzo <a17fed27eaa842282862ff7c1b9c8395a26ac320@terzo.org>

ceph/ceph-docker,ceph/ceph-docker