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