Fix data race in rangeStats.
Fix data race in rangeStats.

Fixes #995

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