Remove unused Dockerfile instruction INSERT

Signed-off-by: Arnaud Porterie <arnaud.porterie@docker.com>

builder/command/command.go

@@ -16,7 +16,6 @@ const (
 	Expose     = "expose"
 	Volume     = "volume"
 	User       = "user"
-	Insert     = "insert"
 )
 
 // Commands is list of all Dockerfile commands
@@ -35,5 +34,4 @@ var Commands = map[string]struct{}{
 	Expose:     {},
 	Volume:     {},
 	User:       {},
-	Insert:     {},
 }

builder/dispatchers.go

@@ -512,8 +512,3 @@ func volume(b *Builder, args []string, attributes map[string]bool, original stri
 	}
 	return nil
 }
-
-// INSERT is no longer accepted, but we still parse it.
-func insert(b *Builder, args []string, attributes map[string]bool, original string) error {
-	return fmt.Errorf("INSERT has been deprecated. Please use ADD instead")
-}

builder/evaluator.go

@@ -71,7 +71,6 @@ func init() {
 		command.Expose:     expose,
 		command.Volume:     volume,
 		command.User:       user,
-		command.Insert:     insert,
 	}
 }
 

builder/parser/parser.go

@@ -61,7 +61,6 @@ func init() {
 		command.Entrypoint: parseMaybeJSON,
 		command.Expose:     parseStringsWhitespaceDelimited,
 		command.Volume:     parseMaybeJSONToList,
-		command.Insert:     parseIgnore,
 	}
 }