mpris2 playback status behaving as if it were static

[Conor Curran]

Binary package hint: indicator-sound

load two players on to the menu, it can be seen that pressing play on one will result in the play back symbol for the other player to change in accordance with the transport state of the player in use.

it can also be seen that dbus-monitor only shows one propertly-changed signal being sent by the correct player.

However the trace from the service shows that the propertly-changed callback in both instances of mpris2controller (one for each player) are triggered by the one dbus signal. What is odd is that the property-changed signal for metadata changes. which uses the exact same code, behaves as it should do.