Repair bgp-rib-impl-config to work with MD5 wiring

Fix scope of test dependencies, use correct API to
lookup dependent bean attributes - dependencyResolver.getAttribute
instead of platform mbean server.
Extend test to instantiate md5 infrastructure to test custom validation.

Change-Id: I5515f81c0c97494869890eb5d9b41f347f423014
Signed-off-by: Tomas Olvecky <tolvecky@cisco.com>
Merge "Repair bgp-rib-impl-config to work with MD5 wiring"