small fix for flush_all test
small fix for flush_all test

rhli/memcached,DSrcl/memcached,alexandermerritt/memcached,gencer/memcached,cloudrain21/memcached,niaomingjian/memcached,emcconville/memcached,samt42/memcached,allen8807/memcached-1,kamyu104/memcached,fengshao0907/memcached,jeremiahyan/memcached,Dhruva6/memcached,memcached/memcached,niaomingjian/memcached,niaomingjian/memcached,memcached/memcached,mitliucak/memcached,jeremiahyan/memcached,cloudrain21/memcached,allen8807/memcached-1,Dhruva6/memcached,rhli/memcached,surajdharmapuram/memcached,emcconville/memcached,myPublicGit/memcached,guikcd/memcached,xiaosl/memcached,elfchief/memcached,williamcheungthu/memcached,guikcd/memcached,allen8807/memcached-1,williamcheungthu/memcached,surajdharmapuram/memcached,rhli/memcached,leedc/memcached,dormando/memcached,EdwardLee03/memcached,fengshao0907/memcached,mitliucak/memcached,myPublicGit/memcached,alexandermerritt/memcached,dormando/memcached,kamyu104/memcached,jeremiahyan/memcached,leedc/memcached,rmccullagh/memcached,elfchief/memcached,emcconville/memcached,elfchief/memcached,EdwardLee03/memcached,angusfenying/memcached-win64,DSrcl/memcached,Dhruva6/memcached,fengshao0907/memcached,bpzhang/memcached,DSrcl/memcached,mitliucak/memcached,xiaosl/memcached,rmccullagh/memcached,Danzeer/memcached,xiaosl/memcached,myPublicGit/memcached,romanticode/memcached,gencer/memcached,Danzeer/memcached,jeremiahyan/memcached,kamyu104/memcached,memcached/memcached,mitliucak/memcached,angusfenying/memcached-win64,myPublicGit/memcached,dormando/memcached,kamyu104/memcached,samanbarghi/memcached,bpzhang/memcached,leedc/memcached,samanbarghi/memcached,fengshao0907/memcached,Danzeer/memcached,gencer/memcached,guikcd/memcached,guikcd/memcached,surajdharmapuram/memcached,elfchief/memcached,surajdharmapuram/memcached,romanticode/memcached,dormando/memcached,emcconville/memcached,samt42/memcached,samt42/memcached,gencer/memcached,cloudrain21/memcached,dianerdianer/memcached,williamcheungthu/memcached,dianerdianer/memcached,williamcheungthu/memcached,dianerdianer/memcached,bpzhang/memcached,EdwardLee03/memcached,angusfenying/memcached-win64,leedc/memcached,allen8807/memcached-1,romanticode/memcached,rhli/memcached,rmccullagh/memcached,samanbarghi/memcached,Dhruva6/memcached,memcached/memcached,dianerdianer/memcached,guikcd/memcached,memcached/memcached,rmccullagh/memcached,angusfenying/memcached-win64,gencer/memcached,alexandermerritt/memcached,niaomingjian/memcached,Danzeer/memcached,DSrcl/memcached,alexandermerritt/memcached,cloudrain21/memcached,romanticode/memcached,xiaosl/memcached,bpzhang/memcached,samt42/memcached,elfchief/memcached,EdwardLee03/memcached,rmccullagh/memcached,dormando/memcached,samanbarghi/memcached