install recovery image using patch mechanism
With the corresponding change in build/tools, the recovery image is
installed via a shell script that is emitted by the OTA builder.
diff --git a/rootdir/init.rc b/rootdir/init.rc
index dab9027..a648ad8 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -287,7 +287,7 @@
service installd /system/bin/installd
socket installd stream 600 system system
-service flash_recovery /system/bin/flash_image recovery /system/recovery.img
+service flash_recovery /system/etc/install-recovery.sh
oneshot
service racoon /system/bin/racoon