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

Change-Id: Ic377d88080ef204026541b3b179e445a05925d2c
(cherry picked from commit c9e0cbe0581be661c9ce6c3c4cdaefddc304b613)
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."