Stop Dynamips hypervisors used by devices before the project is closed.

This is to avoid locked files by hypervisors preventing temporary project working directories to be deleted.

gns3server/handlers/api/project_handler.py

@@ -121,6 +121,8 @@ class ProjectHandler:
 
         pm = ProjectManager.instance()
         project = pm.get_project(request.match_info["project_id"])
+        for module in MODULES:
+            yield from module.instance().project_closing(project)
         yield from project.close()
         for module in MODULES:
             yield from module.instance().project_closed(project)