Bluetooth can receive bugreport data for beaming to another device.
This comes across as an open file descriptor. Allow bluetooth access
to bugreports.

Addresses the following denial:

  avc: denied { read } for path="/data/data/com.android.shell/files/bugreports/bugreport-2014-12-19-15-35-32.txt" dev="dm-0" ino=662738 scontext=u:r:bluetooth:s0 tcontext=u:object_r:shell_data_file:s0 tclass=file permissive=0

Change-Id: I7be2ce2e0e48323c1e8f932be17b434b89daf085