Otherwise we have different security contexts but the same DAC
permissions:
-rw-rw-rw- root     root              u:object_r:sysfs_writable:s0 process_name
-rw-rw-rw- root     root              u:object_r:sysfs:s0 state
-rw-rw-rw- root     root              u:object_r:sysfs:s0 symbol

This change fixes denials such as:
type=1400 msg=audit(1379096020.770:144): avc:  denied  { write } for  pid=85 comm="SurfaceFlinger" name="symbol" dev="sysfs" ino=47 scontext=u:r:surfaceflinger:s0 tcontext=u:object_r:sysfs:s0 tclass=file

Change-Id: I261c7751da3778ee9241ec6b5476e8d9f96ba5ed
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>