Using subprocess with tenacity can lead to issues when a keyboard
interrupt occurs because the logic we have will actually trigger a
retry. This can lead to the inability to stop some of the commands with
a ctrl+c.
Conflicts:
tripleo_common/image/image_uploader.py
Change-Id: I294910384fc9dd9ca8c7114d08842868909d9e9f
Closes-Bug: #1746724
(cherry picked from commit 9003b7ac5b)