Interrupt and close sockets on server stop

The sockets were never interrupted or closed by the client since recent
changes to run the server from a dedicated thread (see commit
0426708).

As a side effect, the server could never terminate properly (it was
waiting on socket blocking calls), so it was always killed by the client
after the WATCHDOG_DELAY.

Interrupt the sockets on stop to give the servera chance to terminate
property, then close them.

app/src/server.c

@@ -763,6 +763,17 @@ run_server(void *data) {
     }
     sc_mutex_unlock(&server->mutex);
 
+    // Interrupt sockets to wake up socket blocking calls on the server
+    assert(server->video_socket != SC_SOCKET_NONE);
+    net_interrupt(server->video_socket);
+    net_close(server->video_socket);
+
+    if (server->control_socket != SC_SOCKET_NONE) {
+        // There is no control_socket if --no-control is set
+        net_interrupt(server->control_socket);
+        net_close(server->control_socket);
+    }
+
     // Give some delay for the server to terminate properly
 #define WATCHDOG_DELAY SC_TICK_FROM_SEC(1)
     sc_tick deadline = sc_tick_now() + WATCHDOG_DELAY;