[vcloud_director] Mocking for tasks.
[vcloud_director] strftime not iso8601 for ruby 1.8.7
[vcloud_director] Consistent usage of ensure_list! in get_disk.
[vcloud_director] Fix ruby 1.9-isms in media_tests.
Merge pull request #2302 from nosborn/vcloud_director_task_mocking

[vcloud_director] Mocking for tasks.