.log files didn't work correctly when evaluating possible docker images
to run so I removed the suffix portion. Also made it easier to run for
specific distros ala:
`make DISTROS="fedora-25 fedora-24 centos-7" CHANNEL_TO_TEST=edge EXPECTED_VERSION="17.06.0-ce" EXPECTED_GITCOMMIT="02c1d87" clean check`
Signed-off-by: Eli Uriegas <eli.uriegas@docker.com>