Update swift_ring_builder to support replicator...

Updates swift_ring_builder rebalancing parsing to support the
latest upstream replicator_id and replicator_port changes.

This correspondes with swift 1.8+ upstream development.

Fixes LP Bug #1182197.

Change-Id: Ibbaf75ca22cad95b22f9b5f03b547db8c47a9ea4