Fix: correctly release server socket.
Fix: correctly release server socket.

qiuwch/unrealcv,qiuwch/unrealcv,unrealcv/unrealcv,unrealcv/unrealcv,unrealcv/unrealcv,qiuwch/unrealcv,qiuwch/unrealcv,qiuwch/unrealcv,unrealcv/unrealcv,unrealcv/unrealcv,qiuwch/unrealcv