soundrecorder: Fix crash on devices without external storage

 * NPE was happening on devices which only have internal storage.
 * Fix the crash, and disable the storage selection menu if you
   are unfortunate enough to have one of these devices.

Change-Id: I4ae435335671a5fd900369a353c5e0e34488e80a
Merge remote-tracking branch 'cm/cm-11.0' into HEAD