eat: use OpenRecoveryScript

/cache/recovery/command would not flash more than 1 update zip.

With OpenRecoveryScript, we can easily do that: http://www.teamw.in/OpenRecoveryScript

Change-Id: I89a8b6ec9d205d1b55824d93afdd46015ae7cef6
Signed-off-by: Roman Birg <romanbirg@gmail.com>