Affected Resource(s)

Please list the resources as a list, for example:

• openstack_networking_router_v2

Actual Behavior

• impossible to unset the external_fixed_ip, since the external_network_id field has to be also unset, but it is computed.
• impossible to change or set enable_snat to false during the router creation, since it requires the ext-gw-mode extension to be enabled.
• impossible to set only the ip_address without specifying the subnet_id
• impossible to change the external_fixed_ip on older neutron versions (upstream neutron already has this fix: https://bugs.launchpad.net/neutron/+bug/1812118)

Important Factoids

see #449 and #628