Remove the deprecated extensions

The Nova extension API was deprecated from OpenStack N release.
this parts of code cannot work well with the newest OpenStack version.

This patch is to remove the relative parts:
1. Remove the step_load_extensions.go
2. Remove the step of extension from builder.go
3. Remove the parameter parsing from step_stop_server.go

Resolves: #5581

builder/openstack/builder.go

@@ -70,7 +70,6 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 
 	// Build the steps
 	steps := []multistep.Step{
-		&StepLoadExtensions{},
 		&StepLoadFlavor{
 			Flavor: b.config.Flavor,
 		},

builder/openstack/step_load_extensions.go

@@ -1,59 +0,0 @@
-package openstack
-
-import (
-	"context"
-	"fmt"
-	"log"
-
-	"github.com/gophercloud/gophercloud/openstack/compute/v2/extensions"
-	"github.com/gophercloud/gophercloud/pagination"
-	"github.com/hashicorp/packer/helper/multistep"
-	"github.com/hashicorp/packer/packer"
-)
-
-// StepLoadExtensions gets the FlavorRef from a Flavor. It first assumes
-// that the Flavor is a ref and verifies it. Otherwise, it tries to find
-// the flavor by name.
-type StepLoadExtensions struct{}
-
-func (s *StepLoadExtensions) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
-	config := state.Get("config").(Config)
-	ui := state.Get("ui").(packer.Ui)
-
-	// We need the v2 compute client
-	client, err := config.computeV2Client()
-	if err != nil {
-		err = fmt.Errorf("Error initializing compute client: %s", err)
-		state.Put("error", err)
-		return multistep.ActionHalt
-	}
-
-	ui.Say("Discovering enabled extensions...")
-	result := make(map[string]struct{}, 15)
-	pager := extensions.List(client)
-	err = pager.EachPage(func(p pagination.Page) (bool, error) {
-		// Extract the extensions from this page
-		exts, err := extensions.ExtractExtensions(p)
-		if err != nil {
-			return false, err
-		}
-
-		for _, ext := range exts {
-			log.Printf("[DEBUG] Discovered extension: %s", ext.Alias)
-			result[ext.Alias] = struct{}{}
-		}
-
-		return true, nil
-	})
-	if err != nil {
-		err = fmt.Errorf("Error loading extensions: %s", err)
-		state.Put("error", err)
-		return multistep.ActionHalt
-	}
-
-	state.Put("extensions", result)
-	return multistep.ActionContinue
-}
-
-func (s *StepLoadExtensions) Cleanup(state multistep.StateBag) {
-}

builder/openstack/step_stop_server.go

@@ -15,15 +15,8 @@ type StepStopServer struct{}
 func (s *StepStopServer) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
 	ui := state.Get("ui").(packer.Ui)
 	config := state.Get("config").(Config)
-	extensions := state.Get("extensions").(map[string]struct{})
 	server := state.Get("server").(*servers.Server)
 
-	// Verify we have the extension
-	if _, ok := extensions["os-server-start-stop"]; !ok {
-		ui.Say("OpenStack cluster doesn't support stop, skipping...")
-		return multistep.ActionContinue
-	}
-
 	// We need the v2 compute client
 	client, err := config.computeV2Client()
 	if err != nil {