Make system_app enforcing.

Change-Id: I9c3ff0a79d947a14084638772451d06298c43e47
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

system_app.te

@@ -4,7 +4,6 @@
 # server.
 #
 type system_app, domain;
-permissive_or_unconfined(system_app)
 app_domain(system_app)
 net_domain(system_app)
 binder_service(system_app)