fixed stuck mod_rtmp session when the call is killed from fs side, such as using uuid_kill

src/mod/endpoints/mod_rtmp/mod_rtmp.c

@@ -233,6 +233,10 @@ switch_status_t rtmp_on_destroy(switch_core_session_t *session)
 		
 		switch_buffer_destroy(&tech_pvt->readbuf);
 		switch_core_timer_destroy(&tech_pvt->timer);
+
+		if (tech_pvt->rtmp_session->state != RS_DESTROY) {
+			rtmp_session_destroy(&tech_pvt->rtmp_session);
+		}
 	}
 
 	return SWITCH_STATUS_SUCCESS;