Fixed following issues:
1. made use of new DataBrokre and removed referece to old DataBrokerService as it is deprecated.
2. fixed a bug in address observer where multiple entries were being made for same address tuple.

Change-Id: I213c2a6df82768a2881bda640cbd9b63d6033ff2
Signed-off-by: Amit Mandke <ammandke@cisco.com>