check auth only when enabled

weed/s3api/s3api_bucket_handlers.go

@@ -111,10 +111,12 @@ func (s3a *S3ApiServer) PutBucketHandler(w http.ResponseWriter, r *http.Request)
 		return
 	}
 
+	if s3a.iam.isEnabled() {
 		if _, errCode = s3a.iam.authRequest(r, s3_constants.ACTION_ADMIN); errCode != s3err.ErrNone {
 			s3err.WriteErrorResponse(w, r, errCode)
 			return
 		}
+	}
 
 	fn := func(entry *filer_pb.Entry) {
 		if identityId := r.Header.Get(xhttp.AmzIdentityId); identityId != "" {