storage: add more unit tests for keyIndex
storage: add more unit tests for keyIndex

cockroachdb/etcd,mickep76/etcd,msanterre/etcd,mqliang/etcd,jonboulle/etcd,gouyang/etcd,plasticbox/etcd,Timer/etcd,plasticbox/etcd,achanda/etcd,fanminshi/etcd,onlyjob/etcd,beni55/etcd,mike-lerch/etcd,svdata/etcd,coreos/etcd,westhood/etcd,honeyqa/etcd,chenbaihu/etcd,purpleidea/etcd,tamird/etcd,endocode/etcd,insequent/etcd,linuxcer/etcd,hongbinz/etcd,buaazp/etcd,handsomesun/etcd,siddontang/etcd,TheHippo/etcd,sayden/etcd,sebrandon1/etcd,xychu/etcd,OyTao/etcd_learning,ktateish/etcd,vimalk78/etcd,nekto0n/etcd,yudai/etcd,dannysauer/etcd,freeloop1114/etcd,gityf/etcd,jeremyeder/etcd,chipironcin/etcd,arthurcolle/etcd,coreos/etcd,HideoYamauchi/etcd,pauldallen/etcd,lorneli/etcd,li-ang/etcd,pauldallen/etcd,a-robinson/etcd,delkyd/etcd,yudai/etcd,cchamplin/etcd,lumjjb/etcd,mike-lerch/etcd,raoofm/etcd,tamird/etcd,tguangch/etcd,lorneli/etcd,gouyang/etcd,betawaffle/etcd,ravigadde/etcd,sofuture/etcd,joshix/etcd,xdlinear/etcd,oscarrr110/etcd,sinsharat/etcd,akauppi/etcd,gae123/etcd,hongchaodeng/etcd,whuwxl/etcd,TheHippo/etcd,sebrandon1/etcd,qqsun8819/etcd,YuleiXiao/etcd,asim/etcd,chenbaihu/etcd,dnaeon/etcd,etcd-io/etcd,Timer/etcd,raoofm/etcd,tguangch/etcd,xiang90/etcd,swingbach/etcd,jlamillan/etcd,gae123/etcd,joshix/etcd,betawaffle/etcd,StorReduce/etcd,li-ang/etcd,shawnps/etcd,Yhgenomics/etcd,westhood/etcd,improbable-io/etcd,msanterre/etcd,buaazp/etcd,zaphod-concur/etcd,cognusion/etcd,etcd-io/etcd,Yhgenomics/etcd,StorReduce/etcd,cognusion/etcd,combk8s/etcd,hroyrh/etcd,YuleiXiao/etcd,HideoYamauchi/etcd,wantonsolutions/dinv-etcd,wantonsolutions/dinv-etcd,ajityagaty/etcd,gityf/etcd,chipironcin/etcd,fasaxc/etcd,endocode/etcd,ktateish/etcd,mickep76/etcd,bluebreezecf/etcd,bluebreezecf/etcd,rchicoli/etcd,gyuho/etcd,Eagle-X/etcd,handsomesun/etcd,OyTao/etcd_learning,fasaxc/etcd,siddontang/etcd,glevand/coreos--etcd,rnaveiras/etcd,vimalk78/etcd,glycerine/etcd,honeyqa/etcd,kkaneda/etcd,giantswarm/etcd,swingbach/etcd,Winslett/etcd,nekto0n/etcd,mkumatag/etcd,dannysauer/etcd,CrazyJvm/etcd,onlyjob/etcd,hroyrh/etcd,luxas/etcd,fgbreel/etcd,hongchaodeng/etcd,freeloop1114/etcd,shawnps/etcd,Winslett/etcd,mqliang/etcd,mqliang/etcd,fasaxc/etcd,ravigadde/etcd,xychu/etcd,zaphod-concur/etcd,fanminshi/etcd,glevand/coreos--etcd,jlamillan/etcd,jefby/etcd,rnaveiras/etcd,luxas/etcd,visheshnp/etcd,whuwxl/etcd,jefby/etcd,iamqizhao/etcd,sinsharat/etcd,a-robinson/etcd,wantonsolutions/dinv-etcd,mkumatag/etcd,svdata/etcd,beni55/etcd,arthurcolle/etcd,visheshnp/etcd,xiang90/etcd,linuxcer/etcd,sofuture/etcd,combk8s/etcd,armstrongli/etcd,cchamplin/etcd,iamqizhao/etcd,delkyd/etcd,achanda/etcd,etcd-io/etcd,bdarnell/etcd,rnaveiras/etcd,jchauncey/etcd,dnaeon/etcd,kkaneda/etcd,cockroachdb/etcd,sayden/etcd,yichengq/etcd,ajityagaty/etcd,oscarrr110/etcd,jonboulle/etcd,jchauncey/etcd,lumjjb/etcd,heyitsanthony/etcd,hongbinz/etcd,wowsoso/etcd,asim/etcd,Eagle-X/etcd,CrazyJvm/etcd,mkumatag/etcd,purpleidea/etcd,glycerine/etcd,xdlinear/etcd,wowsoso/etcd,bdarnell/etcd,yichengq/etcd,heyitsanthony/etcd,jeremyeder/etcd,giantswarm/etcd,rchicoli/etcd,ajityagaty/etcd,improbable-io/etcd,armstrongli/etcd,insequent/etcd,akauppi/etcd,qqsun8819/etcd,gyuho/etcd,fgbreel/etcd