Handled upload errors

      for (let file of files) {

        names.push(file.name);

      }

      client.prepareForUpload(state.path, names)

      return client.prepareForUpload(state.path, names)

        .then(uploadUrls => {

          let uploads = [];

          for (let i = 0; i < files.length; i++) {

            uploads.push(client.uploadFile(uploadUrls[i], files[i]));

          }

          Promise.all(uploads).then(() => {

          Promise.all(uploads)

            .then(() => {

              // Reload current node when all uploads completed

              dispatch('setPath', state.path);

            })

            .catch(error => {

              let message = "Unable to upload file"

              if (error.response && error.response.data) {

                message += ": " + error.response.data;

              }

              main.showError(message);

            });

        });

    },