Make mediaserver enforcing.

Change-Id: I3237c2f3629b2e9be7b2e20f5c3189313efd49e5
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

mediaserver.te

 # mediaserver - multimedia daemon
 type mediaserver, domain;
-permissive mediaserver;
 type mediaserver_exec, exec_type, file_type;
 
 typeattribute mediaserver mlstrustedsubject;