fixed one bug in a UDP test case
fixed one bug in a UDP test case

kerryjiang/SuperSocket,chucklu/SuperSocket,mdavid/SuperSocket,memleaks/SuperSocket,mdavid/SuperSocket,jmptrader/SuperSocket,chucklu/SuperSocket,fryderykhuang/SuperSocket,kerryjiang/SuperSocket,mdavid/SuperSocket,jmptrader/SuperSocket,ZixiangBoy/SuperSocket,chucklu/SuperSocket,fryderykhuang/SuperSocket,ZixiangBoy/SuperSocket,fryderykhuang/SuperSocket,ZixiangBoy/SuperSocket,jmptrader/SuperSocket