[vcloud_director] Better mocking and documentation.
[vcloud_director] Fix minor documentation typo
Merge pull request #2189 from nosborn/vcloud_director_mocks_and_docs

[vcloud_director] Better mocking and documentation.
Merge branch 'master' of https://github.com/fog/fog

# By Nick Osborn
# Via Nick Osborn
* 'master' of https://github.com/fog/fog:
  [vcloud_director] Fix minor documentation typo
  [vcloud_director] Better mocking and documentation.
server model and instance request tests for associate_public_ip