Fix: possible use after free on shutdown

Console commands could access destroyed objects

src/p2pool.cpp

@@ -190,7 +190,6 @@ p2pool::~p2pool()
 	delete m_blockTemplate;
 	delete m_mempool;
 	delete m_params;
-	delete m_consoleCommands;
 }
 
 bool p2pool::calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result)
@@ -471,6 +470,8 @@ void p2pool::on_stop(uv_async_t* async)
 {
 	p2pool* pool = reinterpret_cast<p2pool*>(async->data);
 
+	delete pool->m_consoleCommands;
+
 	if (pool->m_api) {
 		pool->m_api->on_stop();
 	}

src/tcp_server.h

@@ -36,7 +36,7 @@ public:
 
 	bool connect_to_peer(bool is_v6, const char* ip, int port);
 
-	void drop_connections_async() { uv_async_send(&m_dropConnectionsAsync); }
+	void drop_connections_async() { if (m_finished.load() == 0) { uv_async_send(&m_dropConnectionsAsync); } }
 	void shutdown_tcp();
 	virtual void print_status();