Added Swift tests:
      * account: delete account metadata
      * container: retrieve/delete container metadata
      * object: retrieve/copy(2 ways) object
Syntax bug fix in container_client.py:
      return resp. body => return resp, body
Fixed passing headers parameter in head method in rest_client.py:
      return self.request('HEAD', url, headers)
Removed unused imports.

Change-Id: Ica67d6ecae80f851e9e05ebeb4c7d461eba143ee
7 files changed