Allow mpdecision to read mediaserver /proc/pid files.

Addresses denials such as:
avc:  denied  { search } for  pid=2341 comm="mpdecision" name="189" dev="proc" ino=9688 scontext=u:r:mpdecision:s0 tcontext=u:r:mediaserver:s0 tclass=dir

Change-Id: Ie32ea31d2d77929d0f7d4480208b50c099f71c7e
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
diff --git a/sepolicy/mpdecision.te b/sepolicy/mpdecision.te
index 0107b83..c31c296 100644
--- a/sepolicy/mpdecision.te
+++ b/sepolicy/mpdecision.te
@@ -37,3 +37,4 @@
 # This is needed to allow mpdecision to look at system_server's
 # /proc/PID/status file.
 r_dir_file(mpdecision, system_server)
+r_dir_file(mpdecision, mediaserver)