selinux: Add a rule to label the extended keyhandler dex files

These should be treated as regular dex cache files, but they're
expanded outside of the normal cache dir

Change-Id: Id046e1b90116b35d2e7817ed4717fcef78135f08
vendor/cm: We are at CM-12 now.

Change-Id: If92ade1a3992c5e9d828f23a5bccd80df8d27dfc