gui: Fix the sync tree display issue.

Change-Id: If3a2eedb3be56a75f1dc76f09cd3352b6a54241c
diff --git a/src/digest-tree-scene.h b/src/digest-tree-scene.h
index 6ac6b1c..bab1139 100644
--- a/src/digest-tree-scene.h
+++ b/src/digest-tree-scene.h
@@ -65,6 +65,8 @@
   void plotNode(const std::vector<TreeLayout::Coordinate> &v, QString digest, int nodeSize);
   void reDrawNode(DisplayUserPtr p, QColor rimColor);
 
+  QString trimRoutablePrefix(QString prefix);
+
 private:
   Roster m_roster;
   QGraphicsTextItem *m_rootDigest;