Apply a label to /data/mediadrm files.

/data/mediadrm is appearing on devices but is
receiving the system_data_file type. Use the
media_data_file label to help classify these files.
This new label will help with the following denials.
with exisiting allow rules for mediaserver are already
in place.

type=1400 msg=audit(1389139139.551:308): avc:  denied  { open } for  pid=179 comm="mediaserver" name="ay64.dat" dev="mmcblk0p23" ino=136819 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=file
type=1400 msg=audit(1389139140.783:309): avc:  denied  { read } for  pid=179 comm="mediaserver" name="IDM1013" dev="mmcblk0p23" ino=136818 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=dir
type=1400 msg=audit(1389139140.783:310): avc:  denied  { open } for  pid=179 comm="mediaserver" name="IDM1013" dev="mmcblk0p23" ino=136818 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=dir

Change-Id: I84ac78517fdbb0264cf07379120a62675505fc95
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>