daemon/config: improve some tests
daemon/config: improve some tests

- TestReloadWithDuplicateLabels() also check value
- TestReloadDefaultConfigNotExist, TestReloadBadDefaultConfig,
  TestReloadWithConflictingLabels: verify that config is not
  reloaded.

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

moul/docker,Mokolea/docker,trebonian/docker,konstruktoid/docker-upstream,nawawi/docker,thaJeztah/docker,mahak/docker,konstruktoid/docker-upstream,trebonian/docker,cpuguy83/docker,mahak/docker,Mokolea/docker,jimjag/docker,nawawi/docker,nawawi/docker,Ramzec/docker,moby/moby,moul/docker,jimjag/docker,jimjag/docker,trebonian/docker,Ramzec/docker,cpuguy83/docker,cpuguy83/docker,trebonian/docker,konstruktoid/docker-upstream,moby/moby,jimjag/docker,moul/docker,Mokolea/docker,mahak/docker,mahak/docker,moby/moby,Ramzec/docker,konstruktoid/docker-upstream,cpuguy83/docker,Ramzec/docker,moby/moby,moul/docker,thaJeztah/docker,thaJeztah/docker,Mokolea/docker,nawawi/docker,thaJeztah/docker