Performance improvement of router routes operations

This patch fixes inefficiency of updating extra routes.
* remove the code repeated by every routes in validation check.
* remove searching a record to delete per record.

Note: Unit tests are covered by existing ones. So no unit test added.

Change-Id: Ia335ac21c65148063d330e4533a15a73962c43d8
Closes-bug: #1312482
Corrected the syntax of port_update call to NVSD agent

The parameters passed to the agent rpc port_update call in
NVSD plugin were wrong. It is corrected now.

Change-Id: I9ec8f74695b6ca813ffad9e33502d9a2e0bd1f92
Closes-Bug: 1318909
Merge "Performance improvement of router routes operations"
Merge "Corrected the syntax of port_update call to NVSD agent"