Fix swift test

"--output -" is broken. The code now downloads the file and then
compares the contents.

When the test is done, the container is deleted.
Fix EPEL repo URL
Merge pull request #49 from rwsu/swift-test

Fix swift test
removed cherry pick for https://review.openstack.org/#/c/125354/
as it has merged upstream.
Cherry pick a few more changes to fix epel7 repo deployment