Fix counter's bug,issue 74. TODO:add a test for this bug.
Fix counter's bug,issue 74.
TODO:add a test for this bug.


fengshao0907/xmemcached,springning/xmemcached,XHidamariSketchX/xmemcached,fengshao0907/xmemcached,bmahe/xmemcached,mbrukman/xmemcached,mbrukman/xmemcached,killme2008/xmemcached,springning/xmemcached,XHidamariSketchX/xmemcached,killme2008/xmemcached,bmahe/xmemcached