Add persistent property for SELinux enforcment status.

Also adds triggers for going between enforcing and
permissive status.

Bug: 8702843
Change-Id: I841d80999b96acf6b6fd0a5408fb074952d6ae72
diff --git a/init/property_service.c b/init/property_service.c
index 5780001..3248399 100755
--- a/init/property_service.c
+++ b/init/property_service.c
@@ -91,6 +91,7 @@
     { "persist.service.", AID_SYSTEM,   0 },
     { "persist.security.", AID_SYSTEM,   0 },
     { "persist.service.bdroid.", AID_BLUETOOTH,   0 },
+    { "persist.selinux.enforcing", AID_SYSTEM,  0},
     { "selinux."         , AID_SYSTEM,   0 },
     { NULL, 0, 0 }
 };