Network: Defer deletion of client and server game socket handler

This fixes various use after free scenarios in error handling paths

src/network/network_client.cpp

@@ -184,6 +184,8 @@ ClientNetworkGameSocketHandler::~ClientNetworkGameSocketHandler()
 NetworkRecvStatus ClientNetworkGameSocketHandler::CloseConnection(NetworkRecvStatus status)
 {
 	assert(status != NETWORK_RECV_STATUS_OKAY);
+	if (this->IsPendingDeletion()) return status;
+
 	assert(this->sock != INVALID_SOCKET);
 	if (this->status == STATUS_CLOSING) return status;
 
@@ -211,7 +213,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::CloseConnection(NetworkRecvSta
 		this->ReceivePackets();
 	}
 
-	delete this;
+	this->DeferDeletion();
 
 	return status;
 }
@@ -222,6 +224,8 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::CloseConnection(NetworkRecvSta
  */
 void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 {
+	if (this->IsPendingDeletion()) return;
+
 	/* First, send a CLIENT_ERROR to the server, so it knows we are
 	 *  disconnected (and why!) */
 	NetworkErrorCode errorno;