filer: should return 204 on DELETE to nonexistent file

related to

https://github.com/chrislusf/seaweedfs/issues/1776
https://github.com/chrislusf/seaweedfs/issues/1160

weed/server/filer_server_handlers_write.go

@@ -95,7 +95,7 @@ func (fs *FilerServer) DeleteHandler(w http.ResponseWriter, r *http.Request) {
 		glog.V(1).Infoln("deleting", objectPath, ":", err.Error())
 		httpStatus := http.StatusInternalServerError
 		if err == filer_pb.ErrNotFound {
-			httpStatus = http.StatusNotFound
+			httpStatus = http.StatusNoContent
 		}
 		writeJsonError(w, r, httpStatus, err)
 		return