Remove: add missing eol when --force is passed

Signed-off-by: Akim Demaille <akim.demaille@docker.com>

cli/command/image/remove.go

@@ -81,7 +81,7 @@ func runRemove(dockerCli command.Cli, opts removeOptions, images []string) error
 		if !opts.force || fatalErr {
 			return errors.New(msg)
 		}
-		fmt.Fprintf(dockerCli.Err(), msg)
+		fmt.Fprintln(dockerCli.Err(), msg)
 	}
 	return nil
 }

cli/command/image/remove_test.go

@@ -98,7 +98,7 @@ func TestNewRemoveCommandSuccess(t *testing.T) {
 				assert.Equal(t, true, options.Force)
 				return []types.ImageDeleteResponseItem{}, notFound{"image1"}
 			},
-			expectedStderr: "Error: No such image: image1",
+			expectedStderr: "Error: No such image: image1\n",
 		},
 
 		{