firmware-kiev: buildbot: Archive experimental firmware images.

Adapted from change c914a0e3eafb6d6245730bedd9d59981e70dda5
to be compatible with branch.

BUG=chromium-os:30452
TEST=run local trybot on firmware-kiev branch for 'kiev-release'
verify firmware_from_source.tar.bz2 is in artifacts directory.

Change-Id: Ie789103c1abb2b4fe700b28073cdf96bd770f887
Original-Author: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/22790
Tested-by: Dave Parker <dparker@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: David James <davidjames@chromium.org>
2 files changed