Revert "Fix Brocade FC SAN lookup MITM vulnerability"

This reverts commit ab4f57212683baec45d5b682bdd3952ff58249ed.

The change is being reverted as it broke the Brocade FC SAN lookup
functionality.  The change uses configuration options from
ssh_utils that are not initialized when the Brocade driver is
run causing an exception to be thrown complaining that
CONF.ssh_hosts_key_file is used before it is initialized.

The right solution is to change the Brocade driver to use ssh_utils to
make SSH connections.

Conflicts:

	cinder/zonemanager/drivers/brocade/brcd_fc_san_lookup_service.py

Change-Id: I7814c3da9c0e6fcf3143969e74304a48cafcb3d1
Closes-bug: 1398488
(cherry-picked from commit 57103807c5e7fad7276f97ac82f8704f17f4b846)