Allow system_server to hard link its own files

am: d9b0a34a

* commit 'd9b0a34a':
  Allow system_server to hard link its own files

Change-Id: I8417d52812e847b01fa40d720659567aba25f27b

system_server.te

@@ -289,6 +289,8 @@ allow system_server system_data_file:file relabelfrom;
 allow system_server wallpaper_file:file relabelto;
 allow system_server wallpaper_file:file { rw_file_perms unlink };
 
+# Backup of wallpaper imagery uses temporary hard links to avoid data churn
+allow system_server { system_data_file wallpaper_file }:file link;
 
 # ShortcutManager icons
 allow system_server system_data_file:dir relabelfrom;