Create a new location for /data policy files

Adding a new location for policy files under
/data, the new location is /data/security. The
new location is used before attempting to use
any other location.
This requires a new directory to be created by
the init script and an update to the location of
the property_contexts file for property service.

Change-Id: I955a722ac3e51fa6c1b97201b8bdef3f601cf09d
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 257407a..55ee03d 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -246,6 +246,9 @@
     # symlink to bugreport storage location
     symlink /data/data/com.android.shell/files/bugreports /data/bugreports
 
+    # Separate location for storing security policy files on data
+    mkdir /data/security 0600 system system
+
     # If there is no fs-post-data action in the init.<device>.rc file, you
     # must uncomment this line, otherwise encrypted filesystems
     # won't work.