fix ssh and package steps to use source syntax.

builder/vagrant/step_package.go

@@ -25,10 +25,13 @@ func (s *StepPackage) Run(ctx context.Context, state multistep.StateBag) multist
 	}
 	ui.Say("Packaging box...")
 	packageArgs := []string{}
+	box := "source"
 	if s.GlobalID != "" {
-		packageArgs = append(packageArgs, s.GlobalID)
+		box = s.GlobalID
 	}
 
+	packageArgs = append(packageArgs, box)
+
 	if len(s.Include) > 0 {
 		packageArgs = append(packageArgs, "--include", strings.Join(s.Include, ","))
 	}

builder/vagrant/step_ssh_config.go

@@ -30,7 +30,11 @@ func (s *StepSSHConfig) Run(ctx context.Context, state multistep.StateBag) multi
 	driver := state.Get("driver").(VagrantDriver)
 	config := state.Get("config").(*Config)
 
-	sshConfig, err := driver.SSHConfig(s.GlobalID)
+	box := "source"
+	if s.GlobalID != "" {
+		box = s.GlobalID
+	}
+	sshConfig, err := driver.SSHConfig(box)
 	if err != nil {
 		state.Put("error", err)
 		return multistep.ActionHalt