In ContrailVRouterApi, do a connect to the Agent only when the add port / delete port request comes from nova_contrail_vif.
For other requests, do not invoke connect. In case we do a connect and do not send complete vif list, Agent removes them
upon audit. Also, set port_type to NameSpacePort, if it isnt specified.

Closes-bug:#1402603
(cherry picked from commit d7ed3d4a4f1cb94d56d0e495a7d22ad2199bf565)

Change-Id: Ic377d88080ef204026541b3b179e445a05925d2c
Merge "In ContrailVRouterApi, do a connect to the Agent only when the add port / delete port request comes from nova_contrail_vif. For other requests, do not invoke connect. In case we do a connect and do not send complete vif list, Agent removes them upon audit. Also, set port_type to NameSpacePort, if it isnt specified." into R2.0