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

bluetooth.te

@@ -51,6 +51,7 @@ set_prop(bluetooth, pan_result_prop)
 set_prop(bluetooth, ctl_dhcp_pan_prop)
 
 allow bluetooth bluetooth_service:service_manager find;
+allow bluetooth drmserver_service:service_manager find;
 allow bluetooth mediaserver_service:service_manager find;
 allow bluetooth radio_service:service_manager find;
 allow bluetooth surfaceflinger_service:service_manager find;