Assign options.Err in "set image"

There is a usage of options.Err in a Printf, but this option is never set.
This patch passes the stderr into the command and assigns the option correctly.

pkg/kubectl/cmd/set/set_image.go

@@ -78,9 +78,10 @@ var (
 		kubectl set image -f path/to/file.yaml nginx=nginx:1.9.1 --local -o yaml`)
 )
 
-func NewCmdImage(f cmdutil.Factory, out io.Writer) *cobra.Command {
+func NewCmdImage(f cmdutil.Factory, out, err io.Writer) *cobra.Command {
 	options := &ImageOptions{
 		Out: out,
+		Err: err,
 	}
 
 	cmd := &cobra.Command{