Change vdc variable names for consistency

`vdc_name_1` to `vdc_1_name`
`vdc_name_2` to `vdc_2_name`

This relies on a change in vCloud Tools Tester to change the methods that retrieve and deliver these parameters.
This is called a vApp Template in vCloud Director

For some reason it has been called `catalog_item` in all our configuration files. The plan is to change this to be `vapp_template` as it is in vCloud Director, and there is a story for this: https://www.pivotaltracker.com/story/show/70452106, but changing the test code now instead of waiting for that, as that doesn't affect the actual config.
Rename testing file to be specific to this tool
Move include of vCloud Tools Tester to spec helper