etcd: add a read/write timeout to server
etcd: add a read/write timeout to server

The default is for connections to last forever[1]. This leads to fds
leaking. I set the timeout so high by default so that watches don't have
to keep retrying but perhaps we should set it slower.

Tested on a cluster with lots of clients and it seems to have relieved
the problem.

[1] https://groups.google.com/forum/#!msg/golang-nuts/JFhGwh1q9xU/heh4J8pul3QJ

Original Commit: 084dcb5596d52a3a1386d59acced24286137e385
From: philips <ef971ee38bba25d9ac8a840d235457a038448b09@ifup.org>

asim/etcd,CrazyJvm/etcd,cchamplin/etcd,gouyang/etcd,bdarnell/etcd,dnaeon/etcd,joshix/etcd,lumjjb/etcd,OyTao/etcd_learning,olark/etcd,ajityagaty/etcd,jmptrader/etcd,delkyd/etcd,whuwxl/etcd,onlyjob/etcd,nkhare/etcd,bspline/etcd,openedbox/etcd,Eagle-X/etcd,pauldallen/etcd,Winslett/etcd,chenbaihu/etcd,chipironcin/etcd,mwitkow/etcd,westhood/etcd,spacejam/etcd,swingbach/etcd,mkumatag/etcd,qqsun8819/etcd,gyuho/etcd,mischief/etcd,ravigadde/etcd,es-chow/etcd,ylong/etcd,vimalk78/etcd,tempbottle/etcd,mike-lerch/etcd,visheshnp/etcd,jchauncey/etcd,nekto0n/etcd,glensc/etcd,a-robinson/etcd,giantswarm/etcd,hongbinz/etcd,ravigadde/etcd,dalanlan/etcd,insequent/etcd,mwitkow/etcd,imzhulei/etcd,tguangch/etcd,mgoelzer/etcd-fork2,rnaveiras/etcd,raoofm/etcd,sofuture/etcd,chai2010-playground/etcd,fanminshi/etcd,TheHippo/etcd,siddontang/etcd,bdarnell/etcd,ajityagaty/etcd,cockroachdb/etcd,iamqizhao/etcd,buaazp/etcd,jlamillan/etcd,yifan-gu/etcd,fgbreel/etcd,axingblog/etcd,mkumatag/etcd,plasticbox/etcd,njucslqq/etcd,chai2010/etcd,heyitsanthony/etcd,raoofm/etcd,SivagnanamCiena/etcd,xebitstudios/etcd,vimalk78/etcd,linuxcer/etcd,tangkun75/etcd,hzy001/etcd,visheshnp/etcd,luxas/etcd,delkyd/etcd,mkumatag/etcd,mickep76/etcd,chai2010-playground/etcd,cognusion/etcd,gityf/etcd,lzbgt/etcd,gae123/etcd,yichengq/etcd,xebitstudios/etcd,cchamplin/etcd,wantonsolutions/dinv-etcd,fanminshi/etcd,shawnps/etcd,glycerine/etcd,openedbox/etcd,YuleiXiao/etcd,QuantiumTechnology/etcd,coreos/etcd,snailwalker/etcd,es-chow/etcd,princeqjzh/etcd,sayden/etcd,ylong/etcd,bspline/etcd,lumjjb/etcd,achanda/etcd,oscarrr110/etcd,chipironcin/etcd,olark/etcd,xiang90/etcd,wfxiang08/etcd,Winslett/etcd,glevand/coreos--etcd,Yhgenomics/etcd,armstrongli/etcd,imzhulei/etcd,jeremyeder/etcd,barakmich/etcd,gosharplite/etcd,etcd-io/etcd,jeremyeder/etcd,sebschrader/etcd,swingbach/etcd,jlamillan/etcd,gouyang/etcd,glevand/coreos--etcd,mitake/etcd,mike-lerch/etcd,mgoelzer/etcd-fork2,bakins/etcd,wowsoso/etcd,rnaveiras/etcd,akauppi/etcd,mitake/etcd,xychu/etcd,hongchaodeng/etcd,wantonsolutions/dinv-etcd,hongchaodeng/etcd,junxu/etcd,siddontang/etcd,CrazyJvm/etcd,mqliang/etcd,glycerine/etcd,gtank/etcd,gyuho/etcd,plasticbox/etcd,qiaochao911/etcd,steveeJ/etcd,sinsharat/etcd,nieanan/etcd,gae123/etcd,tamird/etcd,lzbgt/etcd,qqsun8819/etcd,shakefu/etcd,akauppi/etcd,crandles/etcd,iamqizhao/etcd,pengzj/etcd,yichengq/etcd,polvi/etcd,Eagle-X/etcd,sebrandon1/etcd,dannysauer/etcd,gtank/etcd,combk8s/etcd,OyTao/etcd_learning,heyitsanthony/etcd,lorneli/etcd,Timer/etcd,rchicoli/etcd,ecnahc515/etcd,purpleidea/etcd,xueshanf/etcd,mischief/etcd,SivagnanamCiena/etcd,insequent/etcd,etcd-io/etcd,sebrandon1/etcd,xiang90/etcd,barakmich/etcd,hroyrh/etcd,TheHippo/etcd,shawnps/etcd,hpcloud/etcd,offscale/etcd,xdlinear/etcd,YuleiXiao/etcd,jefby/etcd,pauldallen/etcd,giantswarm/etcd,coreos/etcd,freeloop1114/etcd,jmptrader/etcd,HideoYamauchi/etcd,zaphod-concur/etcd,handsomesun/etcd,ajityagaty/etcd,nieanan/etcd,etcd-io/etcd,beni55/etcd,xueshanf/etcd,jravetch/etcd,cockroachdb/etcd,njharman/etcd,bluebreezecf/etcd,cognusion/etcd,qiaochao911/etcd,honeyqa/etcd,nekto0n/etcd,freeloop1114/etcd,purpleidea/etcd,devfreesg/etcd,endocode/etcd,onlyjob/etcd,mwitkow-io/etcd,kkaneda/etcd,hpcloud/etcd,li-ang/etcd,QuantiumTechnology/etcd,beni55/etcd,fasaxc/etcd,robszumski/etcd,devfreesg/etcd,kkaneda/etcd,yudai/etcd,a-robinson/etcd,pengzj/etcd,tempbottle/etcd,jravetch/etcd,oscarrr110/etcd,endocode/etcd,msanterre/etcd,xdlinear/etcd,csuideal/etcd,sayden/etcd,jonboulle/etcd,ktateish/etcd,li-ang/etcd,yyljlyy/etcd,msanterre/etcd,betawaffle/etcd,joshix/etcd,hroyrh/etcd,mqliang/etcd,zaphod-concur/etcd,kingland/etcd,hongbinz/etcd,shakefu/etcd,whuwxl/etcd,dnaeon/etcd,jchauncey/etcd,buaazp/etcd,armstrongli/etcd,gityf/etcd,rchicoli/etcd,pigfoot/etcd,elimisteve/etcd,ktateish/etcd,westhood/etcd,insionng/etcd,wowsoso/etcd,lorneli/etcd,mqliang/etcd,StorReduce/etcd,xychu/etcd,spacejam/etcd,honeyqa/etcd,StorReduce/etcd,jonboulle/etcd,dterei/etcd,fgbreel/etcd,combk8s/etcd,elimisteve/etcd,handsomesun/etcd,mwitkow-io/etcd,HideoYamauchi/etcd,crandles/etcd,jefby/etcd,dalanlan/etcd,wfxiang08/etcd,wantonsolutions/dinv-etcd,tangkun75/etcd,Timer/etcd,polvi/etcd,tguangch/etcd,dterei/etcd,fasaxc/etcd,hzy001/etcd,sinsharat/etcd,arthurcolle/etcd,yudai/etcd,improbable-io/etcd,kingland/etcd,luxas/etcd,achanda/etcd,ecnahc515/etcd,youxidev/etcd,shafreeck/etcd,snailwalker/etcd,shafreeck/etcd,bakins/etcd,chai2010/etcd,arthurcolle/etcd,svdata/etcd,yifan-gu/etcd,robszumski/etcd,glensc/etcd,gosharplite/etcd,junxu/etcd,asim/etcd,rnaveiras/etcd,mickep76/etcd,nkhare/etcd,chenbaihu/etcd,njucslqq/etcd,youxidev/etcd,dannysauer/etcd,princeqjzh/etcd,njharman/etcd,steveeJ/etcd,svdata/etcd,sebschrader/etcd,sofuture/etcd,fasaxc/etcd,yyljlyy/etcd,linuxcer/etcd,bluebreezecf/etcd,insionng/etcd,Yhgenomics/etcd,offscale/etcd,justintung/etcd,improbable-io/etcd,betawaffle/etcd,axingblog/etcd,csuideal/etcd,justintung/etcd,tamird/etcd