Refactor "ey rebuild" to use CLI's helper methods.
Refactor "ey rebuild" to use CLI's helper methods.

Change-Id: I0a30def8129bf43a80047cefe23d53114c085c3c
Reviewed-on: http://review.engineyard.com/302
Reviewed-by: Martin Emde <a91ed698dd43fa9a03bc54fdd0c320426601de56@engineyard.com>
Tested-by: Martin Emde <a91ed698dd43fa9a03bc54fdd0c320426601de56@engineyard.com>

cowboyd/engineyard,radamanthus/engineyard,engineyard/engineyard,engineyard/engineyard,radamanthus/engineyard