Invalidate progress bar every time the holding cell is requested for uploads in progress

src/com/owncloud/android/ui/adapter/ExpandableUploadListAdapter.java

@@ -293,6 +293,7 @@ public class ExpandableUploadListAdapter extends BaseExpandableListAdapter imple
                     uploadDateTextView.setVisibility(View.GONE);
                     pathTextView.setVisibility(View.GONE);
                     fileSizeTextView.setVisibility(View.GONE);
+                    progressBar.invalidate();
                     break;
 
                 case UPLOAD_FAILED: