ExternalStorageProvider: use mount point in device list

For me its is extremely unlogical that only the volume label is used
in the device list. Even more because it can be an empty string
and for a normal android user this information is not visible
anywhere else.

Using the mount point and if available the device label
separated by "-" makes much more sense and shows the same
information as all other apps that access external storage

Change-Id: I3fc3675af6640e37aa999b03ae2de2858237c638
Revert "MediaDrm#mNativeContext is a long, not int."

This reverts commit e6bbdcb91b1673c29d2698a4319edbd88efa9d30.
Media: Make sure mVolumeController is not null

* mVolumeController is throwing NPEs all over the place in this class, which
  causes apps like Chromecast to shit the bed when using Google Play Music
  and/or Google Play Movies
* Catch additional exception on try/catch already in place and throw in a null
  check to prevent apps from crashing until null mVolumeController is rectified

Change-Id: I7a883aa85256d5dc6af6f37978676b136cb40d0d
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>