integration: add support for grpc server and client
integration: add support for grpc server and client

sofuture/etcd,nekto0n/etcd,dnaeon/etcd,heyitsanthony/etcd,zaphod-concur/etcd,handsomesun/etcd,heyitsanthony/etcd,ktateish/etcd,swingbach/etcd,yudai/etcd,Timer/etcd,akauppi/etcd,ajityagaty/etcd,jlamillan/etcd,hongchaodeng/etcd,StorReduce/etcd,endocode/etcd,vimalk78/etcd,glycerine/etcd,armstrongli/etcd,etcd-io/etcd,gyuho/etcd,StorReduce/etcd,glevand/coreos--etcd,ktateish/etcd,sinsharat/etcd,jlamillan/etcd,joshix/etcd,jonboulle/etcd,mickep76/etcd,raoofm/etcd,linuxcer/etcd,sinsharat/etcd,etcd-io/etcd,OyTao/etcd_learning,insequent/etcd,handsomesun/etcd,chipironcin/etcd,luxas/etcd,shawnps/etcd,xiang90/etcd,armstrongli/etcd,gyuho/etcd,fanminshi/etcd,rnaveiras/etcd,akauppi/etcd,raoofm/etcd,mqliang/etcd,ravigadde/etcd,tguangch/etcd,tguangch/etcd,westhood/etcd,insequent/etcd,mkumatag/etcd,swingbach/etcd,coreos/etcd,chipironcin/etcd,ravigadde/etcd,dannysauer/etcd,dnaeon/etcd,lorneli/etcd,mqliang/etcd,nekto0n/etcd,qqsun8819/etcd,yudai/etcd,rchicoli/etcd,mkumatag/etcd,wantonsolutions/dinv-etcd,lumjjb/etcd,tamird/etcd,coreos/etcd,li-ang/etcd,dannysauer/etcd,mqliang/etcd,sofuture/etcd,lumjjb/etcd,luxas/etcd,CrazyJvm/etcd,bdarnell/etcd,bluebreezecf/etcd,joshix/etcd,rnaveiras/etcd,cockroachdb/etcd,achanda/etcd,fanminshi/etcd,zaphod-concur/etcd,plasticbox/etcd,sebrandon1/etcd,linuxcer/etcd,siddontang/etcd,YuleiXiao/etcd,sebrandon1/etcd,OyTao/etcd_learning,achanda/etcd,xiang90/etcd,ajityagaty/etcd,a-robinson/etcd,Timer/etcd,whuwxl/etcd,lorneli/etcd,purpleidea/etcd,li-ang/etcd,rchicoli/etcd,YuleiXiao/etcd,wantonsolutions/dinv-etcd,westhood/etcd,purpleidea/etcd,mickep76/etcd,shawnps/etcd,visheshnp/etcd,rnaveiras/etcd,jonboulle/etcd,whuwxl/etcd,plasticbox/etcd,wantonsolutions/dinv-etcd,siddontang/etcd,a-robinson/etcd,endocode/etcd,qqsun8819/etcd,glevand/coreos--etcd,bluebreezecf/etcd,hongchaodeng/etcd,ajityagaty/etcd,visheshnp/etcd,tamird/etcd,etcd-io/etcd,CrazyJvm/etcd,mkumatag/etcd,bdarnell/etcd,cockroachdb/etcd,vimalk78/etcd,glycerine/etcd