Inconsistencies in network configuration state apply

[cywang117]

Problem

On a release update where the only thing that changes is the network configuration, a network won't be removed if it has a custom configuration and the target config of that network is the default config

Reproduction

With the following two releases:

version: '2.4'

services:
  one:
    image: alpine
    command: sh -c "echo one-new && sleep infinity"
    stop_signal: SIGKILL
    networks:
      - test
  two:
    image: alpine
    command: sh -c "echo two-new && sleep infinity"
    stop_signal: SIGKILL
    networks:
      - test

networks:
  test:
    ipam:
      driver: default
      config:
        - subnet: 172.28.0.0/16
          gateway: 172.28.5.254

version: '2.4'

services:
  one:
    image: alpine
    command: sh -c "echo one-new && sleep infinity"
    stop_signal: SIGKILL
    networks:
      - test
  two:
    image: alpine
    command: sh -c "echo two-new && sleep infinity"
    stop_signal: SIGKILL
    networks:
      - test

networks:
  test:

Pin back and forth between them, and observe that once a network has been configured with the custom ipam configs, it won't ever be recreated with the default configs even if pinning to the latter release.