* Fix getting Supervisor IP address in testing
Newer Docker versions (probably newer than 29.x) do not have a global
IPAddress attribute under .NetworkSettings anymore. There is a network
specific map under Networks. For our case the hassio has the relevant
IP address. This network specific maps already existed before, hence
the new inspect format works for old as well as new Docker versions.
While at it, also adjust the test fixture.
* Actively wait for hassio IPAddress to become valid
