df-controller does not create tunnel to newer controllers

[Dima Kuznetsov]

In a multinode environment, when a new chassis registers itself, it pulls all the already-registered chassis and creates a tunnel port for them. From that point, update on chassis table is not acted upon, so tunnels to newer chassis are not set up.

[dimak@dimatron: ~/projects/dragonflow/dragonflow ((0c1ce21...))]$ git grep update_chassis
controller/df_local_controller.py: def update_chassis(self, chassis):
controller/df_local_controller.py: self.db_store.update_chassis(chassis.get_id(), chassis)
controller/df_local_controller.py: self.db_store.update_chassis(c.get_id(), c)
controller/df_local_controller.py: self.nb_api.update_chassis(self.chassis_name, **kwargs)
db/api_nb.py: def update_chassis(self, id, **columns):
db/db_store.py: def update_chassis(self, chassis_id, chassis):
tests/unit/test_app_base.py: self.controller.db_store.update_chassis('fake_host', fake_chassis1)
tests/unit/test_app_base.py: self.controller.db_store.update_chassis('fake_host2', fake_chassis2)
tests/unit/test_db_store.py: self.db_store.update_chassis('chassis1', chassis1)
tests/unit/test_db_store.py: self.db_store.update_chassis('chassis2', chassis2)

It seems that all the update_chassis calls go to either db-store or nb-api, but no one calls update_chassis code defined in df local controller.

[Dima Kuznetsov (dimakuz)]

Using virtual tunnel ports solves the issue:
https://review.openstack.org/#/c/387017/