server: return binary string for bit type
server: return binary string for bit type

CodeRushing/tidb,simon-xia/tidb,qhsong/tidb,silenceper/tidb,silenceper/tidb,EvilMcJerkface/tidb,cosmtrek/tidb,kyle-wang/tidb,netroby/tidb,ngaut/tidb,pingcap/tidb,mccxj/tidb,myrice/tidb,silentred/tidb,ngaut/tidb,kyle-wang/tidb,c4pt0r/tidb,tiancaiamao/tidb,8cbx/tidb,qhsong/tidb,ming-relax/tidb,kyle-wang/tidb,CodeRushing/tidb,XuHuaiyu/tidb,qiuyesuifeng/tidb,yangwenmai/tidb,zimulala/tidb,zs634134578/tidb,Cofyc/tidb,wusphinx/tidb,c4pt0r/tidb,louishust/tidb,ngaut/tidb,silentred/tidb,ueizhou/tidb,coocood/tidb,kyle-wang/tidb,astaxie/tidb,pingcap/tidb,c4pt0r/tidb,kyle-wang/tidb,zimulala/tidb,qiuyesuifeng/tidb,Nify/tidb,ngaut/tidb,ming-relax/tidb,gaocegege/tidb,pingcap/tidb,anywhy/tidb,yangwenmai/tidb,wusphinx/tidb,Nify/tidb,andelf/tidb,JinheLin/tidb,zs634134578/tidb,c4pt0r/tidb,yuanwhy/tidb,XuHuaiyu/tidb,spongedu/tidb,ngaut/tidb,pingcap/tidb,liyu4/tidb,coocood/tidb,netroby/tidb,andelf/tidb,ngaut/tidb,spongedu/tidb,liyu4/tidb,pingcap/tidb,JinheLin/tidb,louishust/tidb,Cofyc/tidb,astaxie/tidb,pingcap/tidb,myrice/tidb,cosmtrek/tidb,simon-xia/tidb,c4pt0r/tidb,8cbx/tidb,c4pt0r/tidb,anywhy/tidb,mccxj/tidb,tiancaiamao/tidb,EvilMcJerkface/tidb,gaocegege/tidb,kyle-wang/tidb,ueizhou/tidb,yuanwhy/tidb