grt: rm default arg for CUGR::write in cugr

Signed-off-by: Matt Liberty <[email protected]>

Author: maliberty

src/grt/src/cugr/include/CUGR.h

@@ -68,7 +68,7 @@ class CUGR
        stt::SteinerTreeBuilder* stt_builder);
   void init(int min_routing_layer, int max_routing_layer);
   void route();
-  void write(const std::string& guide_file = "");
+  void write(const std::string& guide_file);
   NetRouteMap getRoutes();
 
  private: