Label /data/misc/media and allow mediaserver access to it.

Otherwise we get denials like these on 4.4:

type=1400 audit(1383590170.360:29): avc:  denied  { write } for  pid=61 comm="mediaserver" name="media" dev="mtdblock1" ino=6416 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=dir
type=1400 audit(1383590170.360:29): avc:  denied  { add_name } for  pid=61 comm="mediaserver" name="emulator.camera.hotplug.0" scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=dir
type=1400 audit(1383590170.360:29): avc:  denied  { create } for  pid=61 comm="mediaserver" name="emulator.camera.hotplug.0" scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=file
type=1400 audit(1383590170.360:29): avc:  denied  { write open } for  pid=61 comm="mediaserver" name="emulator.camera.hotplug.0" dev="mtdblock1" ino=6431 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=file
type=1400 audit(1383590255.100:231): avc:  denied  { write } for  pid=832 comm="mediaserver" name="emulator.camera.hotplug.0" dev="mtdblock1" ino=6431 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=file
type=1400 audit(1383590255.100:231): avc:  denied  { open } for  pid=832 comm="mediaserver" name="emulator.camera.hotplug.0" dev="mtdblock1" ino=6431 scontext=u:r:mediaserver:s0 tcontext=u:object_r:system_data_file:s0 tclass=file

Change-Id: Ic374488f8b62bd4f8b3c90f30da0e8d1ed1a7343
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>