Move VMC::CLI.start spec code into a helper method

Change-Id: I7b4c6c841c020fd75609c4a7fc7d38a9a1a452d3
begin conversion to new vmc invocation format in specs

We changed this to reflect what the user types in the commandline rather than some implementation detail of mothership

Change-Id: Iba2d5289d623e3854ce9c0be8f8ec8d1ecfd92eb