Fix Brocade FC SAN lookup MITM vulnerability

Modify the Brocade FC SAN lookup service implementation to use the
same SSH key config properties used elsewhere rather than relying on
arguments which are non-standard and never passed by the base lookup
service.

Change-Id: I0cb5141368bc9a62a4e0374026d66fc2725cfe24
Closes-Bug: 1391311
(cherry picked from commit ab4f57212683baec45d5b682bdd3952ff58249ed)