epee: signal cond var before unlocking

This is more canonical, and avoids some helgrind spam

contrib/epee/include/net/abstract_tcp_server2.inl

@@ -1010,7 +1010,7 @@ POP_WARNINGS
     boost::unique_lock<boost::mutex> lock(local_shared_context->connect_mut);
     auto connect_callback = [](boost::system::error_code ec_, boost::shared_ptr<local_async_context> shared_context)
     {
-      shared_context->connect_mut.lock(); shared_context->ec = ec_; shared_context->connect_mut.unlock(); shared_context->cond.notify_one(); 
+      shared_context->connect_mut.lock(); shared_context->ec = ec_; shared_context->cond.notify_one(); shared_context->connect_mut.unlock();
     };
 
     sock_.async_connect(remote_endpoint, boost::bind<void>(connect_callback, _1, local_shared_context));