bluetooth: Ignore Device.DisconnectRequested
Handling the signal DisconnectRequested should be unnecessary since the
profile-specific interfaces will be later disconnected, leading to
module unload.
Additionally, the signal is problematic: if an interface (i.e.
A2DP AudioSource) is playing at the time DisconnectRequested is
signaled, the following sequence can occur:
1. AudioSource is playing
2. DisconnectRequested is received
3. Module is unloaded due to DisconnectRequested
4. AudioSource state changes from playing to connected
5. module-bluetooth-discover loads the module
6. AudioSource state changes from connected to disconnected
Therefore the module is unnecessarily loaded, to be unloaded immediately
afterwards. This can easily be reproduced if a device is unpaired while
the audio is streaming.
The simplest solution to this consists of removing step 3, by just
ignoring the DisconnectRequested signal. This reverts commit
8169a6a6c921215c1353e8a34fccbdc4e2e20440.