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

init/init.c

@@ -745,6 +745,7 @@ static int bootchart_init_action(int nargs, char **args)
 #endif
 
 static const struct selinux_opt seopts_prop[] = {
+        { SELABEL_OPT_PATH, "/data/security/property_contexts" },
         { SELABEL_OPT_PATH, "/data/system/property_contexts" },
         { SELABEL_OPT_PATH, "/property_contexts" },
         { 0, NULL }

rootdir/init.rc

@@ -246,6 +246,9 @@ on post-fs-data
     # 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.