Fix debug feature and add --debug to swift.

- Remove PYTHON_SWIFTCLIENT and use --debug making it more consistents
  with other openstack clients libraries.
- Fix printing the curl command.
- Don't show the body of the GET objects it could get bad on large
  objects and it's an iterator anyway.
- Use -I for showing HEADs (and not -X HEAD).

Change-Id: I954e7d3d795401fc3679725440dec36cdc80af87