Due to the big changes recently to support k8s rolling upgrade, a
regression issue was introduced which is broken the proxy function
for image downloading. This patch fixes it for both fedor atomic
driver and fedora coreos driver.

Task: 37784
Story: 2007005

Change-Id: I11113d69629e1a97a58e5270f67c7404292b45c3
(cherry picked from commit ad2ef496)