etcdserver: refactor server tests
etcdserver: refactor server tests

1. remove redundant fake struct
2. use fake node for better testing
3. code clean

arthurcolle/etcd,devfreesg/etcd,gosharplite/etcd,gityf/etcd,delkyd/etcd,xychu/etcd,glensc/etcd,sofuture/etcd,Timer/etcd,fgbreel/etcd,dalanlan/etcd,insionng/etcd,SivagnanamCiena/etcd,spacejam/etcd,whuwxl/etcd,swingbach/etcd,xdlinear/etcd,mqliang/etcd,sebrandon1/etcd,es-chow/etcd,whuwxl/etcd,akauppi/etcd,lumjjb/etcd,yifan-gu/etcd,olark/etcd,shakefu/etcd,fanminshi/etcd,pengzj/etcd,HideoYamauchi/etcd,chipironcin/etcd,xychu/etcd,youxidev/etcd,lzbgt/etcd,purpleidea/etcd,yudai/etcd,wowsoso/etcd,joshix/etcd,joshix/etcd,dalanlan/etcd,cockroachdb/etcd,li-ang/etcd,sofuture/etcd,fasaxc/etcd,jravetch/etcd,arthurcolle/etcd,linuxcer/etcd,cchamplin/etcd,coreos/etcd,Eagle-X/etcd,shafreeck/etcd,vimalk78/etcd,offscale/etcd,improbable-io/etcd,xueshanf/etcd,betawaffle/etcd,endocode/etcd,improbable-io/etcd,freeloop1114/etcd,nkhare/etcd,glevand/coreos--etcd,njharman/etcd,openedbox/etcd,nieanan/etcd,gouyang/etcd,betawaffle/etcd,jonboulle/etcd,sebrandon1/etcd,ravigadde/etcd,OyTao/etcd_learning,junxu/etcd,rnaveiras/etcd,tangkun75/etcd,rnaveiras/etcd,mitake/etcd,luxas/etcd,axingblog/etcd,TheHippo/etcd,yichengq/etcd,cockroachdb/etcd,gae123/etcd,hpcloud/etcd,mike-lerch/etcd,csuideal/etcd,westhood/etcd,fasaxc/etcd,coreos/etcd,Timer/etcd,snailwalker/etcd,yudai/etcd,xiang90/etcd,gouyang/etcd,hroyrh/etcd,insequent/etcd,njucslqq/etcd,jeremyeder/etcd,mgoelzer/etcd-fork2,li-ang/etcd,mischief/etcd,mike-lerch/etcd,raoofm/etcd,xueshanf/etcd,bdarnell/etcd,youxidev/etcd,chenbaihu/etcd,mwitkow-io/etcd,qqsun8819/etcd,olark/etcd,a-robinson/etcd,akauppi/etcd,sayden/etcd,etcd-io/etcd,nieanan/etcd,yyljlyy/etcd,tguangch/etcd,delkyd/etcd,heyitsanthony/etcd,iamqizhao/etcd,combk8s/etcd,handsomesun/etcd,raoofm/etcd,axingblog/etcd,bakins/etcd,msanterre/etcd,buaazp/etcd,ecnahc515/etcd,ravigadde/etcd,jeremyeder/etcd,TheHippo/etcd,dnaeon/etcd,fanminshi/etcd,hongchaodeng/etcd,oscarrr110/etcd,mqliang/etcd,hongchaodeng/etcd,gosharplite/etcd,qqsun8819/etcd,snailwalker/etcd,princeqjzh/etcd,bspline/etcd,zaphod-concur/etcd,devfreesg/etcd,achanda/etcd,buaazp/etcd,pauldallen/etcd,mischief/etcd,shafreeck/etcd,asim/etcd,hongbinz/etcd,offscale/etcd,mwitkow-io/etcd,pengzj/etcd,gyuho/etcd,Yhgenomics/etcd,jmptrader/etcd,hzy001/etcd,westhood/etcd,gyuho/etcd,cognusion/etcd,ajityagaty/etcd,onlyjob/etcd,yifan-gu/etcd,glensc/etcd,achanda/etcd,xebitstudios/etcd,tempbottle/etcd,nekto0n/etcd,barakmich/etcd,tamird/etcd,polvi/etcd,etcd-io/etcd,elimisteve/etcd,combk8s/etcd,imzhulei/etcd,Winslett/etcd,bluebreezecf/etcd,tempbottle/etcd,bspline/etcd,linuxcer/etcd,rchicoli/etcd,siddontang/etcd,QuantiumTechnology/etcd,elimisteve/etcd,YuleiXiao/etcd,hongbinz/etcd,zaphod-concur/etcd,lzbgt/etcd,mgoelzer/etcd-fork2,visheshnp/etcd,mwitkow/etcd,gityf/etcd,justintung/etcd,hzy001/etcd,polvi/etcd,glycerine/etcd,mkumatag/etcd,swingbach/etcd,a-robinson/etcd,chipironcin/etcd,tguangch/etcd,endocode/etcd,jefby/etcd,ecnahc515/etcd,sinsharat/etcd,plasticbox/etcd,jefby/etcd,Eagle-X/etcd,luxas/etcd,glycerine/etcd,lorneli/etcd,yichengq/etcd,mitake/etcd,gtank/etcd,giantswarm/etcd,xebitstudios/etcd,shawnps/etcd,msanterre/etcd,ylong/etcd,dnaeon/etcd,wfxiang08/etcd,dannysauer/etcd,wantonsolutions/dinv-etcd,jchauncey/etcd,mqliang/etcd,yyljlyy/etcd,njucslqq/etcd,HideoYamauchi/etcd,handsomesun/etcd,kkaneda/etcd,heyitsanthony/etcd,beni55/etcd,imzhulei/etcd,jmptrader/etcd,shakefu/etcd,SivagnanamCiena/etcd,kkaneda/etcd,rchicoli/etcd,lumjjb/etcd,jravetch/etcd,lorneli/etcd,njharman/etcd,nekto0n/etcd,princeqjzh/etcd,crandles/etcd,pauldallen/etcd,armstrongli/etcd,fgbreel/etcd,ktateish/etcd,bdarnell/etcd,dannysauer/etcd,ktateish/etcd,tamird/etcd,jlamillan/etcd,purpleidea/etcd,mkumatag/etcd,bakins/etcd,gtank/etcd,spacejam/etcd,mkumatag/etcd,StorReduce/etcd,Yhgenomics/etcd,insionng/etcd,steveeJ/etcd,chenbaihu/etcd,asim/etcd,etcd-io/etcd,OyTao/etcd_learning,csuideal/etcd,honeyqa/etcd,kingland/etcd,ajityagaty/etcd,onlyjob/etcd,crandles/etcd,mickep76/etcd,jonboulle/etcd,sinsharat/etcd,vimalk78/etcd,CrazyJvm/etcd,ajityagaty/etcd,svdata/etcd,mwitkow/etcd,oscarrr110/etcd,openedbox/etcd,cognusion/etcd,bluebreezecf/etcd,svdata/etcd,visheshnp/etcd,beni55/etcd,barakmich/etcd,nkhare/etcd,sebschrader/etcd,fasaxc/etcd,xiang90/etcd,sebschrader/etcd,jchauncey/etcd,giantswarm/etcd,Winslett/etcd,hpcloud/etcd,wowsoso/etcd,insequent/etcd,StorReduce/etcd,ylong/etcd,CrazyJvm/etcd,wantonsolutions/dinv-etcd,armstrongli/etcd,iamqizhao/etcd,wfxiang08/etcd,qiaochao911/etcd,honeyqa/etcd,sayden/etcd,qiaochao911/etcd,glevand/coreos--etcd,shawnps/etcd,YuleiXiao/etcd,xdlinear/etcd,cchamplin/etcd,steveeJ/etcd,es-chow/etcd,justintung/etcd,kingland/etcd,hroyrh/etcd,junxu/etcd,rnaveiras/etcd,plasticbox/etcd,mickep76/etcd,gae123/etcd,tangkun75/etcd,jlamillan/etcd,QuantiumTechnology/etcd,siddontang/etcd,freeloop1114/etcd,wantonsolutions/dinv-etcd