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
Add env[SWIFTCLIENT_INSECURE]

Add env[SWIFTCLIENT_INSECURE] as default of --insecure option.
If set to 'true', allow to access insecure keystone server.
The name follows 'NOVACLIENT_INSECURE' in novaclient.

Change-Id: I322674eba9c07e6def97bce339815fa15191a92d
Merge "Add env[SWIFTCLIENT_INSECURE]"