env.StartInstance(s.callCtx, s.createStartInstanceArgs(c))  c.Assert(err, jc.ErrorIsNil)   call := s.client.Calls()[0]  createVMArgs := call.Args[0].(vsphereclient.CreateVirtualMachineParams)  c.Assert(*createVMArgs.Constraints.RootDiskSource, gc.Equals, "