avoid race in NewClient
avoid race in NewClient

this fixes a bug in which a freshly open connection
which closes right away leads to an unclosed client
without a local address (prone to NPEs).

alunarbeach/cockroach,loucash/cockroach,arypurnomoz/cockroach,veteranlu/cockroach,slavau/cockroach,alunarbeach/cockroach,c4pt0r/cockroach,jess-edwards/cockroach,bg451/cockroach,GokulSrinivas/cockroach,SustainFund/cockroach,arypurnomoz/cockroach,nkhuyu/cockroach,glycerine/cockroach,freakynit/cockroach,Abioy/cockroach,marcuswestin/cockroach,veteranlu/cockroach,mbertschler/cockroach,nkhuyu/cockroach,Abioy/cockroach,SustainFund/cockroach,jmank88/cockroach,GokulSrinivas/cockroach,vaibhavarora/cockroach,fengshao0907/cockroach,freakynit/cockroach,cockroachdb/cockroach,slavau/cockroach,arjun4084346/cockroach,vaibhavarora/cockroach,nkhuyu/cockroach,jmank88/cockroach,chrisseto/cockroach,maxlang/cockroach,freakynit/cockroach,glycerine/cockroach,briceburg/cockroach,nkhuyu/cockroach,abhishekgahlot/cockroach,mbonaci/cockroach,glycerine/cockroach,vivekmenezes/cockroach,il9ue/cockroach,glycerine/cockroach,vaibhavarora/cockroach,veteranlu/cockroach,briceburg/cockroach,arjun4084346/cockroach,sunya123/cockroach,veteranlu/cockroach,nieyy/cockroach,jmank88/cockroach,jamesgraves/cockroach,petermattis/cockroach,XisiHuang/cockroach,marcuswestin/cockroach,paperstreet/cockroach,yosiat/cockroach,sunya123/cockroach,chrisseto/cockroach,mbonaci/cockroach,chrisseto/cockroach,XisiHuang/cockroach,hassyma/cockroach,veteranlu/cockroach,nieyy/cockroach,loucash/cockroach,vivekmenezes/cockroach,GokulSrinivas/cockroach,paperstreet/cockroach,arjun4084346/cockroach,bg451/cockroach,vaibhavarora/cockroach,abhishekgahlot/cockroach,c4pt0r/cockroach,jgautheron/cockroach,c4pt0r/cockroach,maxlang/cockroach,jmank88/cockroach,sunya123/cockroach,SustainFund/cockroach,jamesgraves/cockroach,linearb/cockroach,il9ue/cockroach,cuongdo/cockroach,GokulSrinivas/cockroach,ajayaa/cockroach,c4pt0r/cockroach,jgautheron/cockroach,arjun4084346/cockroach,paperstreet/cockroach,cockroachdb/cockroach,linearb/cockroach,yiixiansheng/cockroach,bg451/cockroach,ajayaa/cockroach,slavau/cockroach,chrisseto/cockroach,nkhuyu/cockroach,vivekmenezes/cockroach,Abioy/cockroach,vivekmenezes/cockroach,alex/cockroach,linearb/cockroach,ajayaa/cockroach,petermattis/cockroach,alex/cockroach,alunarbeach/cockroach,cockroachdb/cockroach,jess-edwards/cockroach,Abioy/cockroach,paperstreet/cockroach,ajayaa/cockroach,cockroachdb/cockroach,vivekmenezes/cockroach,yiixiansheng/cockroach,alex/cockroach,bg451/cockroach,loucash/cockroach,maxlang/cockroach,briceburg/cockroach,arypurnomoz/cockroach,cuongdo/cockroach,yiixiansheng/cockroach,hassyma/cockroach,freakynit/cockroach,linearb/cockroach,arypurnomoz/cockroach,jamesgraves/cockroach,jess-edwards/cockroach,SustainFund/cockroach,alunarbeach/cockroach,Abioy/cockroach,vaibhavarora/cockroach,vivekmenezes/cockroach,vaibhavarora/cockroach,cuongdo/cockroach,SustainFund/cockroach,bg451/cockroach,jess-edwards/cockroach,hassyma/cockroach,marcuswestin/cockroach,cuongdo/cockroach,il9ue/cockroach,linearb/cockroach,mbertschler/cockroach,alex/cockroach,fengshao0907/cockroach,bg451/cockroach,sunya123/cockroach,fengshao0907/cockroach,jamesgraves/cockroach,il9ue/cockroach,arjun4084346/cockroach,mbonaci/cockroach,SustainFund/cockroach,loucash/cockroach,paperstreet/cockroach,jgautheron/cockroach,paperstreet/cockroach,jamesgraves/cockroach,jamesgraves/cockroach,vivekmenezes/cockroach,nieyy/cockroach,alex/cockroach,jmank88/cockroach,maxlang/cockroach,mbertschler/cockroach,slavau/cockroach,paperstreet/cockroach,nieyy/cockroach,yosiat/cockroach,arjun4084346/cockroach,mbertschler/cockroach,sunya123/cockroach,GokulSrinivas/cockroach,hassyma/cockroach,sunya123/cockroach,ajayaa/cockroach,glycerine/cockroach,fengshao0907/cockroach,XisiHuang/cockroach,veteranlu/cockroach,maxlang/cockroach,yosiat/cockroach,petermattis/cockroach,yiixiansheng/cockroach,jmank88/cockroach,chrisseto/cockroach,maxlang/cockroach,yosiat/cockroach,briceburg/cockroach,jess-edwards/cockroach,petermattis/cockroach,nieyy/cockroach,veteranlu/cockroach,il9ue/cockroach,alunarbeach/cockroach,marcuswestin/cockroach,arjun4084346/cockroach,mbertschler/cockroach,arjun4084346/cockroach,vaibhavarora/cockroach,petermattis/cockroach,marcuswestin/cockroach,nieyy/cockroach,petermattis/cockroach,cuongdo/cockroach,sunya123/cockroach,jess-edwards/cockroach,alex/cockroach,petermattis/cockroach,petermattis/cockroach,alunarbeach/cockroach,XisiHuang/cockroach,hassyma/cockroach,slavau/cockroach,jgautheron/cockroach,jamesgraves/cockroach,marcuswestin/cockroach,c4pt0r/cockroach,bg451/cockroach,c4pt0r/cockroach,abhishekgahlot/cockroach,mbonaci/cockroach,maxlang/cockroach,jgautheron/cockroach,ajayaa/cockroach,loucash/cockroach,marcuswestin/cockroach,hassyma/cockroach,mbertschler/cockroach,XisiHuang/cockroach,Abioy/cockroach,jgautheron/cockroach,vaibhavarora/cockroach,glycerine/cockroach,chrisseto/cockroach,jmank88/cockroach,yosiat/cockroach,abhishekgahlot/cockroach,cockroachdb/cockroach,yiixiansheng/cockroach,yosiat/cockroach,cockroachdb/cockroach,cockroachdb/cockroach,slavau/cockroach,cockroachdb/cockroach,GokulSrinivas/cockroach,linearb/cockroach,il9ue/cockroach,XisiHuang/cockroach,fengshao0907/cockroach,paperstreet/cockroach,briceburg/cockroach,mbonaci/cockroach,nkhuyu/cockroach,nieyy/cockroach,mbertschler/cockroach,mbonaci/cockroach,veteranlu/cockroach,maxlang/cockroach,briceburg/cockroach,il9ue/cockroach,freakynit/cockroach,yiixiansheng/cockroach,linearb/cockroach,sunya123/cockroach,nieyy/cockroach,glycerine/cockroach,abhishekgahlot/cockroach,arypurnomoz/cockroach,loucash/cockroach,abhishekgahlot/cockroach,cuongdo/cockroach,vivekmenezes/cockroach,fengshao0907/cockroach,il9ue/cockroach,cuongdo/cockroach,arypurnomoz/cockroach,freakynit/cockroach,jess-edwards/cockroach,marcuswestin/cockroach,glycerine/cockroach,cuongdo/cockroach