Privileged apps require access to cache

gmscore uses cache for updates

Bug: 24977552
Change-Id: I45a713fcfc70b71a2de712e77b64fb9feab67dd7

priv_app.te

@@ -29,6 +29,10 @@ allow priv_app persistent_data_block_service:service_manager find;
 # TODO: narrow this to just MediaProvider
 allow priv_app mnt_media_rw_file:dir search;
 
+# Write to /cache.
+allow priv_app cache_file:dir create_dir_perms;
+allow priv_app cache_file:file create_file_perms;
+
 # Access to /data/media.
 allow priv_app media_rw_data_file:dir create_dir_perms;
 allow priv_app media_rw_data_file:file create_file_perms;