Allow bluetooth to find the drmservice

Address the following denial:
  SELinux  E  avc:  denied  { find } for service=drm.drmManager scontext=u:r:bluetooth:s0 tcontext=u:object_r:drmserver_service:s0

This denial is triggered by Bluetooth when MmsFileProvider.java is
using the PduPersister which in turn is using DRM.

Change-Id: I4c077635f8afa39e6bc5e10178c3a7ae3cb6a9ea