fix Tagging test

weed/s3api/tags.go

@@ -16,6 +16,7 @@ type TagSet struct {
 type Tagging struct {
 	XMLName xml.Name `xml:"Tagging"`
 	TagSet  TagSet   `xml:"TagSet"`
+	Xmlns   string   `xml:"xmlns,attr"`
 }
 
 func (t *Tagging) ToTags() map[string]string {

weed/s3api/tags_test.go

@@ -32,6 +32,7 @@ func TestXMLUnmarshall(t *testing.T) {
 
 func TestXMLMarshall(t *testing.T) {
 	tags := &Tagging{
+		Xmlns: "http://s3.amazonaws.com/doc/2006-03-01/",
 		TagSet: TagSet{
 			[]Tag{
 				{