Network: Fix potential crash with maptoscene.

src/View/Network/GraphWidget.py

@@ -819,8 +819,10 @@ class GraphWidget(QGraphicsView):
         if self._state == "move":
             # Move on scene
             if (not self.selected_item() and
-                    event.buttons() & Qt.LeftButton):
-                old_p = self.mapToScene(self.m_origin_x, self.m_origin_y)
+                (event.buttons() & Qt.LeftButton)):
+                old_p = self.mapToScene(
+                    int(self.m_origin_x), int(self.m_origin_y)
+                )
                 new_p = self.mapToScene(event.pos())
                 translation = new_p - old_p