AttributeError: 'Project' object has no attribute 'emit'

Fix #804

gns3server/controller/export_project.py

@@ -68,7 +68,7 @@ def export_project(project, temporary_dir, include_images=False, keep_compute_id
             except OSError as e:
                 msg = "Could not export file {}: {}".format(path, e)
                 log.warn(msg)
-                project.emit("log.warning", {"message": msg})
+                project.controller.notification.emit("log.warning", {"message": msg})
                 continue
             if file.endswith(".gns3"):
                 pass