OpenStack: Change option name to `image_disk_format`

builder/openstack/image_config.go

@@ -14,7 +14,7 @@ type ImageConfig struct {
 	ImageMetadata   map[string]string            `mapstructure:"metadata"`
 	ImageVisibility imageservice.ImageVisibility `mapstructure:"image_visibility"`
 	ImageMembers    []string                     `mapstructure:"image_members"`
-	DiskFormat      string                       `mapstructure:"disk_format"`
+	ImageDiskFormat string                       `mapstructure:"image_disk_format"`
 }
 
 func (c *ImageConfig) Prepare(ctx *interpolate.Context) []error {

builder/openstack/step_create_image.go

@@ -47,7 +47,7 @@ func (s *stepCreateImage) Run(_ context.Context, state multistep.StateBag) multi
 		}
 		volume := state.Get("volume_id").(string)
 		image, err := volumeactions.UploadImage(blockStorageClient, volume, volumeactions.UploadImageOpts{
-			DiskFormat: config.DiskFormat,
+			DiskFormat: config.ImageDiskFormat,
 			ImageName:  config.ImageName,
 		}).Extract()
 		if err != nil {