recovery: fix rebooting

Change I84c0513acb549720cb0e8c9fcbda0050f5c396f5 moved reboot
functionality into init but did not update the recovery partition; so
"adb reboot" and /system/bin/reboot in recovery are both broken.

Change-Id: Ie2d14627a686ffb5064256b6c399723636dff116
diff --git a/etc/init.rc b/etc/init.rc
index b26d2ae..9d1da1d 100644
--- a/etc/init.rc
+++ b/etc/init.rc
@@ -38,6 +38,9 @@
 
     class_start default
 
+on property:sys.powerctl=*
+   powerctl ${sys.powerctl}
+
 service ueventd /sbin/ueventd
     critical