[vcloud_director] Fix listing catalog items when only a single item exists.
[vcloud_director] Move ensure_list to VCloudDirector::Collection.
Replace inline wrap implementations in Tasks and Organizations with
ensure_list.
[rackspace] Don't parse JSON in delete_server

The Rackspace API replies with an empty response to delete_server
requests, but includes a header enforcing the application/json
content-type.

This commit disables JSON parsing on delete_server requests,
which prevents the appearance of these warnings:

[WARNING] Error Parsing response json - 781: unexpected token at ''
fix for - fog fails to load vdc with 1 or 0 vapps

Fog code fails to describe the vdc with zero or single vapps(resource
entities).
This is because the underlying API does not return Array, when vdc
has single or no vapp. Added a fix for this.
corrected the check for empty string

checking for an empty string , in case when vdc with zero resource entities are
returned
Merge pull request #2163 from DavidWittman/rs-delete-server-json

[rackspace] Don't parse JSON in delete_server response
Merge pull request #2166 from snehaso/master

[vcloud-director] fixed fog to load vdc with single or zero resource entities
[rackspace] updating to only parse json if the body of the response has data
Merge pull request #2169 from rackspace/no_body

[rackspace] updating to only parse json if the body of the response has data
[rackspace] remove deprecated response block from request
[openstack|storage] remove deprecated response block from request
Merge pull request #2173 from burns/remove_deprecated_block_os

[openstack|storage] remove deprecated response block from request
[vcloud_director|tests] Remove vcr_cassettes_old/
[vcloud_director|tests] Don't hardcode API host.
[vcloud_director|tests] mv *_test.rb *.tests.rb
[vcloud_director|tests] Make tests work
[vcloud_director|tests] Remove and ignore vcr_cassettes/
Merge pull request #2172 from burns/remove_deprecated_block

[rackspace] remove deprecated response block from request
Merge pull request #2176 from nosborn/vcloud_director_tests

[vcloud_director|tests] Fixes and cleanup
Merge pull request #2155 from rsalm/vcloud_director_catalog_items_fix

[vcloud_director] Fix listing catalog items when only a single item exists