Move 'start music player on headset connection' option out of DSPManager
(1/2)

This option isn't related to DSP manager at all, so it shouldn't be
implemented there.

Change-Id: Ibe35c9739ccb4f4587ee71f514d16fb317bf4034
Fix up 'launch player on headset connection' option.

- don't crash system_server if no music player can be found
- use the active user's setting instead of the owner's setting

Change-Id: I38a07fe5c8c3d67ececd0768e1fcc01a6cf7fa5a