Have init set up the backup stage dir on /cache

Bug 26834865

Change-Id: Idc63c1706f68d42b2a9cee05997c63a9bbcb0fb9
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 441f28b..289bdec 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -283,6 +283,10 @@
     # permissions if created by the recovery system.
     mkdir /cache/recovery 0770 system cache
 
+    # Backup/restore mechanism uses the cache partition
+    mkdir /cache/backup_stage 0700 system system
+    mkdir /cache/backup 0700 system system
+
     #change permissions on vmallocinfo so we can grab it from bugreports
     chown root log /proc/vmallocinfo
     chmod 0440 /proc/vmallocinfo