Close tty on exit (#7411)

main.go

@@ -192,6 +192,8 @@ func wrappedMain() int {
 			TTY, err = tty.Open()
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "No tty available: %s\n", err)
+			} else {
+				defer TTY.Close()
 			}
 		}
 		ui = &packer.BasicUi{

packer/tty.go

@@ -2,4 +2,5 @@ package packer
 
 type TTY interface {
 	ReadString() (string, error)
+	Close() error
 }

packer/ui_test.go

@@ -42,6 +42,7 @@ type testTTY struct {
 	say string
 }
 
+func (tty *testTTY) Close() error { return nil }
 func (tty *testTTY) ReadString() (string, error) {
 	return tty.say, nil
 }