Revert "cros_generate_update_payload: kill old style update image generation"
Revert "cros_generate_update_payload: kill old style update image generation"

This reverts commit fad7fecc4d7a9f39efd88110ddcae85e7242830a.

BUG=n0ne
TEST=

Review URL: http://codereview.chromium.org/6246073

Change-Id: I7652b57145931b9d6ed85d82f648eb6f5dc35ae2

fivethreeo/scripts,bcwaldon/coreos-scripts,BugRoger/scripts,nicescale/scripts,bcwaldon/coreos-scripts,fivethreeo/scripts,smilart/scripts,glevand/coreos--scripts,mischief/scripts,bcwaldon/coreos-scripts,endocode/scripts,sigma/coreos-scripts,crawford/scripts,sigma/coreos-scripts,mischief/scripts,andrejro/coreos--scripts,gtank/scripts,BugRoger/scripts,andrejro/coreos--scripts,vmware/coreos-scripts,sigma/coreos-scripts,crawford/scripts,zhang0137/scripts,endocode/scripts,marineam/coreos-scripts,fivethreeo/scripts,zhang0137/scripts,coreos/scripts,nicescale/scripts,mjg59/scripts,andrejro/coreos--scripts,mjg59/scripts,trnubo/scripts,gtank/scripts,trnubo/scripts,glevand/coreos--scripts,gtank/scripts,coreos/scripts,crawford/scripts,marineam/coreos-scripts,BugRoger/scripts,marineam/coreos-scripts,endocode/scripts,vmware/coreos-scripts,smilart/scripts,smilart/scripts,mjg59/scripts,vmware/coreos-scripts,zhang0137/scripts,mischief/scripts,trnubo/scripts,nicescale/scripts