chore(ci): properly shutting down HTTP/2 server

Apply the same fixes as for AMF.

Nonetheless, it takes forever for the SMF to shutdown in HTTP/2 variant (compared to HTTP/1 that is almost immediate).

src/api-server/smf-http2-server.h

@@ -81,6 +81,7 @@ class smf_http2_server {
   uint32_t m_port;
   http2 server;
   smf::smf_app* m_smf_app;
+  bool running_server;
 
  protected:
 };