[socks] fix a compiler warning on MSVC
[socks] fix a compiler warning on MSVC

KangLin/qxmpp,Kaffeine/qxmpp,LightZam/qxmpp,KangLin/qxmpp,LightZam/qxmpp,LightZam/qxmpp,Kaffeine/qxmpp,Kaffeine/qxmpp,KangLin/qxmpp