Remove stateful generation logic from the dev server.
Remove stateful generation logic from the dev server.

Change-Id: I713894a0c704393a71e437ea62a021f355522fb8

BUG=chromium-os:8885
TEST=Ran it with -p --image to force stateful update generation with new
payload scripts in crosutils.

Review URL: http://codereview.chromium.org/4703007

mgireesh05/dev-util,marineam/coreos-dev-util,marineam/coreos-dev-util,mgireesh05/dev-util,coreos/dev-util,coreos/dev-util,coreos/dev-util,mgireesh05/dev-util