Some L3 ports can directly modify the IP address now,
but there are some types of device_owner, for instance
network:router_centralized_snat, should not allow to
change the IP address, otherwise it will increase L3
agent code complexity.
Since router public gateway port is related to the
external network, and this port can be used for some
service, like VPN. So after this patch we will only
allow the gateway port to update the IP address
directly, aka device_owner network:router_gateway.
The following l3 router ports will not be allowed to
directly update the IP address:
network:ha_router_replicated_interface
network:router_centralized_snat
network:router_ha_interface
network:router_interface
network:router_interface_distributed
Remove one unit test case since it will not occur in
neutron.
Change-Id: I2890a71abc82cb781b601afb879bdcca10e39257
Closes-Bug: #1796824
20f8271b6b