etcdctlv3:updated readme.md for make-mirror modify/remove prefix in dest cluster
etcdctlv3:updated readme.md for make-mirror modify/remove prefix in dest cluster

whuwxl/etcd,lorneli/etcd,handsomesun/etcd,li-ang/etcd,sebrandon1/etcd,dannysauer/etcd,lumjjb/etcd,sebrandon1/etcd,cockroachdb/etcd,gyuho/etcd,plasticbox/etcd,armstrongli/etcd,insequent/etcd,mkumatag/etcd,coreos/etcd,xiang90/etcd,hongchaodeng/etcd,rnaveiras/etcd,rchicoli/etcd,etcd-io/etcd,a-robinson/etcd,ravigadde/etcd,bdarnell/etcd,fanminshi/etcd,vimalk78/etcd,zaphod-concur/etcd,visheshnp/etcd,endocode/etcd,nekto0n/etcd,a-robinson/etcd,CrazyJvm/etcd,OyTao/etcd_learning,ajityagaty/etcd,bluebreezecf/etcd,glevand/coreos--etcd,ajityagaty/etcd,jlamillan/etcd,bluebreezecf/etcd,heyitsanthony/etcd,sinsharat/etcd,ravigadde/etcd,dannysauer/etcd,tguangch/etcd,mqliang/etcd,vimalk78/etcd,mqliang/etcd,etcd-io/etcd,akauppi/etcd,lumjjb/etcd,jlamillan/etcd,insequent/etcd,fanminshi/etcd,tguangch/etcd,zaphod-concur/etcd,luxas/etcd,rnaveiras/etcd,glevand/coreos--etcd,nekto0n/etcd,etcd-io/etcd,mqliang/etcd,bdarnell/etcd,heyitsanthony/etcd,qqsun8819/etcd,akauppi/etcd,rchicoli/etcd,luxas/etcd,xiang90/etcd,mickep76/etcd,li-ang/etcd,cockroachdb/etcd,mickep76/etcd,mkumatag/etcd,YuleiXiao/etcd,hongchaodeng/etcd,OyTao/etcd_learning,sinsharat/etcd,visheshnp/etcd,mkumatag/etcd,CrazyJvm/etcd,lorneli/etcd,YuleiXiao/etcd,coreos/etcd,joshix/etcd,yudai/etcd,qqsun8819/etcd,yudai/etcd,joshix/etcd,handsomesun/etcd,endocode/etcd,plasticbox/etcd,gyuho/etcd,rnaveiras/etcd,whuwxl/etcd,armstrongli/etcd,ajityagaty/etcd