Remove deprecated mod_image_for_test.sh and references.

mod_image_for_test.sh doesn't work anymore so nobody should be using it.
There are a few places where scripts try to use mod_image_for_test.sh,
and these are timebombs because they fail if a test image needs to actually
be produced.

BUG=chromium-os:31183
TEST=Tested that this script doesn't produce any images anymore, so
     it should be fine to delete it.

Change-Id: If80337407023d62f76117dc44cadfa46801ca236
Reviewed-on: https://gerrit.chromium.org/gerrit/40955
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: David James <davidjames@chromium.org>
Tested-by: David James <davidjames@chromium.org>
5 files changed