RM9285: Fix for upstream db change & py26 issue

* neutron commit 9bf0e6654480f98f2315a43687b267263a82a823 removed
helper methdods from neutron.db.api.
* py26 does not have dict comprehensions.
Limiting validate_gateway_excluded to gateway_ip only

RM9134
Merge pull request #215 from insequent/round_2_nexthop_and_gateway_ip

Limiting validate_gateway_excluded to gateway_ip only
Merge pull request #216 from asadoughi/master

RM9285: Fix for upstream db change & py26 issue
RM8615

Implements a redis client for publishing security group rules for ports
connected to briged networks.