Fix warning when CPU only (#4751)
Fix warning when CPU only (#4751)


CodingCat/mxnet,hotpxl/mxnet,sxjscience/mxnet,crazy-cat/incubator-mxnet,likelyzhao/mxnet,arikpoz/mxnet,kevinthesun/mxnet,ptrendx/mxnet,tlby/mxnet,jamesliu/mxnet,arikpoz/mxnet,tlby/mxnet,rahul003/mxnet,TuSimple/mxnet,TuSimple/mxnet,EvanzzzZ/mxnet,indhub/mxnet,precedenceguo/mxnet,sergeykolychev/mxnet,jiajiechen/mxnet,apaleyes/mxnet,sxjscience/mxnet,kkk669/mxnet,kkk669/mxnet,Guneet-Dhillon/mxnet,weleen/mxnet,indhub/mxnet,EvanzzzZ/mxnet,jennyzhang0215/incubator-mxnet,leezu/mxnet,coder-james/mxnet,weleen/mxnet,larroy/mxnet,leezu/mxnet,tlby/mxnet,yajiedesign/mxnet,kevinthesun/mxnet,yajiedesign/mxnet,DR08/mxnet,mbaijal/incubator-mxnet,madjam/mxnet,nicklhy/mxnet,piiswrong/mxnet,dmlc/mxnet,TuSimple/mxnet,arikpoz/mxnet,vikingMei/mxnet,jiajiechen/mxnet,luoyetx/mxnet,rishita/mxnet,smolix/incubator-mxnet,smolix/incubator-mxnet,zhreshold/mxnet,ForkedReposBak/mxnet,precedenceguo/mxnet,ShownX/incubator-mxnet,sergeykolychev/mxnet,nicklhy/mxnet,yajiedesign/mxnet,dmlc/mxnet,gautamkmr/incubator-mxnet,ZihengJiang/mxnet,xcgoner/dist-mxnet,fullfanta/mxnet,kkk669/mxnet,formath/mxnet,kevinthesun/mxnet,wangyum/mxnet,szha/mxnet,Prasad9/incubator-mxnet,tlby/mxnet,weleen/mxnet,piiswrong/mxnet,solin319/incubator-mxnet,ShownX/incubator-mxnet,hotpxl/mxnet,pluskid/mxnet,EvanzzzZ/mxnet,dmlc/mxnet,jennyzhang0215/incubator-mxnet,mbaijal/incubator-mxnet,jamesliu/mxnet,szha/mxnet,antoan2/incubator-mxnet,thirdwing/mxnet,navrasio/mxnet,CodingCat/mxnet,gautamkmr/incubator-mxnet,thirdwing/mxnet,wangyum/mxnet,eric-haibin-lin/mxnet,reminisce/mxnet,Ldpe2G/mxnet,ForkedReposBak/mxnet,yuruofeifei/mxnet,ptrendx/mxnet,jamesliu/mxnet,smolix/incubator-mxnet,LinkHS/incubator-mxnet,TuSimple/mxnet,piiswrong/mxnet,luoyetx/mxnet,reminisce/mxnet,kkk669/mxnet,eric-haibin-lin/mxnet,DR08/mxnet,ptrendx/mxnet,navrasio/mxnet,Mega-DatA-Lab/mxnet,crazy-cat/incubator-mxnet,likelyzhao/mxnet,wangyum/mxnet,precedenceguo/mxnet,formath/mxnet,jennyzhang0215/incubator-mxnet,Ldpe2G/mxnet,pluskid/mxnet,xcgoner/dist-mxnet,stefanhenneking/mxnet,danithaca/mxnet,jamesliu/mxnet,ykim362/mxnet,navrasio/mxnet,ptrendx/mxnet,smolix/incubator-mxnet,Guneet-Dhillon/mxnet,stefanhenneking/mxnet,jennyzhang0215/incubator-mxnet,mbaijal/incubator-mxnet,luoyetx/mxnet,hesseltuinhof/mxnet,xcgoner/dist-mxnet,larroy/mxnet,coder-james/mxnet,piiswrong/mxnet,hpi-xnor/BMXNet,hesseltuinhof/mxnet,smolix/incubator-mxnet,apache/incubator-mxnet,stefanhenneking/mxnet,fullfanta/mxnet,danithaca/mxnet,Northrend/mxnet,arank/mxnet,saurabh3949/mxnet,crazy-cat/incubator-mxnet,Ldpe2G/mxnet,larroy/mxnet,mbaijal/incubator-mxnet,danithaca/mxnet,EvanzzzZ/mxnet,yuruofeifei/mxnet,ptrendx/mxnet,luoyetx/mxnet,ZihengJiang/mxnet,kevinthesun/mxnet,sxjscience/mxnet,stefanhenneking/mxnet,hesseltuinhof/mxnet,Guneet-Dhillon/mxnet,jamesliu/mxnet,zhreshold/mxnet,dmlc/mxnet,wangyum/mxnet,likelyzhao/mxnet,luoyetx/mxnet,DR08/mxnet,vikingMei/mxnet,DickJC123/mxnet,piiswrong/mxnet,solin319/incubator-mxnet,formath/mxnet,apaleyes/mxnet,jamesliu/mxnet,DR08/mxnet,rahul003/mxnet,hesseltuinhof/mxnet,yajiedesign/mxnet,precedenceguo/mxnet,sxjscience/mxnet,larroy/mxnet,antoan2/incubator-mxnet,precedenceguo/mxnet,EvanzzzZ/mxnet,lxn2/mxnet,dmlc/mxnet,ykim362/mxnet,coder-james/mxnet,arank/mxnet,fullfanta/mxnet,fullfanta/mxnet,Guneet-Dhillon/mxnet,larroy/mxnet,weleen/mxnet,saurabh3949/mxnet,apaleyes/mxnet,vikingMei/mxnet,wangyum/mxnet,crazy-cat/incubator-mxnet,ZihengJiang/mxnet,nicklhy/mxnet,jermainewang/mxnet,Guneet-Dhillon/mxnet,tlby/mxnet,saurabh3949/mxnet,mbaijal/incubator-mxnet,Mega-DatA-Lab/mxnet,formath/mxnet,Ldpe2G/mxnet,indhub/mxnet,reminisce/mxnet,DickJC123/mxnet,hotpxl/mxnet,likelyzhao/mxnet,tornadomeet/mxnet,antoan2/incubator-mxnet,mbaijal/incubator-mxnet,thirdwing/mxnet,EvanzzzZ/mxnet,gautamkmr/incubator-mxnet,Prasad9/incubator-mxnet,Northrend/mxnet,coder-james/mxnet,dmlc/mxnet,rahul003/mxnet,sergeykolychev/mxnet,CodingCat/mxnet,saurabh3949/mxnet,arikpoz/mxnet,weleen/mxnet,antoan2/incubator-mxnet,pluskid/mxnet,reminisce/mxnet,pluskid/mxnet,tornadomeet/mxnet,eric-haibin-lin/mxnet,indhub/mxnet,saurabh3949/mxnet,ptrendx/mxnet,luoyetx/mxnet,dmlc/mxnet,Prasad9/incubator-mxnet,rahul003/mxnet,tornadomeet/mxnet,ShownX/incubator-mxnet,ykim362/mxnet,piiswrong/mxnet,rahul003/mxnet,ZihengJiang/mxnet,Mega-DatA-Lab/mxnet,luoyetx/mxnet,ykim362/mxnet,kkk669/mxnet,arank/mxnet,apache/incubator-mxnet,EvanzzzZ/mxnet,sxjscience/mxnet,rishita/mxnet,Ldpe2G/mxnet,antoan2/incubator-mxnet,TuSimple/mxnet,jiajiechen/mxnet,zhreshold/mxnet,szha/mxnet,rishita/mxnet,Prasad9/incubator-mxnet,smolix/incubator-mxnet,pluskid/mxnet,gautamkmr/incubator-mxnet,wangyum/mxnet,jennyzhang0215/incubator-mxnet,Prasad9/incubator-mxnet,Northrend/mxnet,LinkHS/incubator-mxnet,DickJC123/mxnet,weleen/mxnet,arikpoz/mxnet,eric-haibin-lin/mxnet,xcgoner/dist-mxnet,lxn2/mxnet,ptrendx/mxnet,tlby/mxnet,gautamkmr/incubator-mxnet,smolix/incubator-mxnet,apaleyes/mxnet,TuSimple/mxnet,LinkHS/incubator-mxnet,yajiedesign/mxnet,eric-haibin-lin/mxnet,likelyzhao/mxnet,szha/mxnet,stefanhenneking/mxnet,piiswrong/mxnet,apaleyes/mxnet,likelyzhao/mxnet,kevinthesun/mxnet,thirdwing/mxnet,apaleyes/mxnet,smolix/incubator-mxnet,coder-james/mxnet,leezu/mxnet,vikingMei/mxnet,navrasio/mxnet,saurabh3949/mxnet,ykim362/mxnet,reminisce/mxnet,TuSimple/mxnet,antoan2/incubator-mxnet,mbaijal/incubator-mxnet,arikpoz/mxnet,eric-haibin-lin/mxnet,DR08/mxnet,ykim362/mxnet,saurabh3949/mxnet,wangyum/mxnet,yuruofeifei/mxnet,vikingMei/mxnet,Mega-DatA-Lab/mxnet,weleen/mxnet,Ldpe2G/mxnet,arank/mxnet,ZihengJiang/mxnet,kkk669/mxnet,larroy/mxnet,ForkedReposBak/mxnet,tlby/mxnet,ZihengJiang/mxnet,Northrend/mxnet,hpi-xnor/BMXNet,jermainewang/mxnet,thirdwing/mxnet,Mega-DatA-Lab/mxnet,madjam/mxnet,tornadomeet/mxnet,LinkHS/incubator-mxnet,jamesliu/mxnet,dmlc/mxnet,kkk669/mxnet,rishita/mxnet,DR08/mxnet,arank/mxnet,apaleyes/mxnet,Northrend/mxnet,hpi-xnor/BMXNet,ForkedReposBak/mxnet,solin319/incubator-mxnet,fullfanta/mxnet,DR08/mxnet,danithaca/mxnet,xcgoner/dist-mxnet,yajiedesign/mxnet,madjam/mxnet,hpi-xnor/BMXNet,ShownX/incubator-mxnet,danithaca/mxnet,CodingCat/mxnet,danithaca/mxnet,zhreshold/mxnet,fullfanta/mxnet,yajiedesign/mxnet,luoyetx/mxnet,Prasad9/incubator-mxnet,ykim362/mxnet,jiajiechen/mxnet,kkk669/mxnet,yuruofeifei/mxnet,larroy/mxnet,ykim362/mxnet,pluskid/mxnet,hesseltuinhof/mxnet,wangyum/mxnet,jiajiechen/mxnet,yuruofeifei/mxnet,jermainewang/mxnet,stefanhenneking/mxnet,LinkHS/incubator-mxnet,likelyzhao/mxnet,jiajiechen/mxnet,LinkHS/incubator-mxnet,hesseltuinhof/mxnet,Northrend/mxnet,kevinthesun/mxnet,lxn2/mxnet,rishita/mxnet,LinkHS/incubator-mxnet,ForkedReposBak/mxnet,reminisce/mxnet,apache/incubator-mxnet,thirdwing/mxnet,tornadomeet/mxnet,formath/mxnet,sxjscience/mxnet,TuSimple/mxnet,crazy-cat/incubator-mxnet,jennyzhang0215/incubator-mxnet,solin319/incubator-mxnet,pluskid/mxnet,tornadomeet/mxnet,EvanzzzZ/mxnet,navrasio/mxnet,apaleyes/mxnet,eric-haibin-lin/mxnet,jermainewang/mxnet,solin319/incubator-mxnet,hpi-xnor/BMXNet,fullfanta/mxnet,navrasio/mxnet,rahul003/mxnet,reminisce/mxnet,xcgoner/dist-mxnet,rahul003/mxnet,indhub/mxnet,indhub/mxnet,danithaca/mxnet,gautamkmr/incubator-mxnet,gautamkmr/incubator-mxnet,szha/mxnet,solin319/incubator-mxnet,szha/mxnet,formath/mxnet,Mega-DatA-Lab/mxnet,nicklhy/mxnet,hpi-xnor/BMXNet,tlby/mxnet,rahul003/mxnet,crazy-cat/incubator-mxnet,kevinthesun/mxnet,Guneet-Dhillon/mxnet,arank/mxnet,reminisce/mxnet,jiajiechen/mxnet,indhub/mxnet,gautamkmr/incubator-mxnet,ShownX/incubator-mxnet,precedenceguo/mxnet,LinkHS/incubator-mxnet,apache/incubator-mxnet,Northrend/mxnet,Prasad9/incubator-mxnet,antoan2/incubator-mxnet,sergeykolychev/mxnet,eric-haibin-lin/mxnet,formath/mxnet,hpi-xnor/BMXNet,rahul003/mxnet,kevinthesun/mxnet,jermainewang/mxnet,luoyetx/mxnet,jermainewang/mxnet,solin319/incubator-mxnet,vikingMei/mxnet,tornadomeet/mxnet,zhreshold/mxnet,TuSimple/mxnet,ptrendx/mxnet,eric-haibin-lin/mxnet,nicklhy/mxnet,jiajiechen/mxnet,TuSimple/mxnet,crazy-cat/incubator-mxnet,arank/mxnet,Mega-DatA-Lab/mxnet,nicklhy/mxnet,vikingMei/mxnet,pluskid/mxnet,gautamkmr/incubator-mxnet,saurabh3949/mxnet,szha/mxnet,madjam/mxnet,indhub/mxnet,leezu/mxnet,Mega-DatA-Lab/mxnet,antoan2/incubator-mxnet,CodingCat/mxnet,tlby/mxnet,xcgoner/dist-mxnet,zhreshold/mxnet,CodingCat/mxnet,CodingCat/mxnet,DR08/mxnet,ZihengJiang/mxnet,jennyzhang0215/incubator-mxnet,arikpoz/mxnet,ptrendx/mxnet,sergeykolychev/mxnet,madjam/mxnet,weleen/mxnet,jiajiechen/mxnet,hotpxl/mxnet,yajiedesign/mxnet,crazy-cat/incubator-mxnet,leezu/mxnet,yuruofeifei/mxnet,hesseltuinhof/mxnet,lxn2/mxnet,smolix/incubator-mxnet,navrasio/mxnet,madjam/mxnet,jermainewang/mxnet,CodingCat/mxnet,fullfanta/mxnet,ForkedReposBak/mxnet,lxn2/mxnet,arank/mxnet,nicklhy/mxnet,leezu/mxnet,sergeykolychev/mxnet,ykim362/mxnet,xcgoner/dist-mxnet,jamesliu/mxnet,rishita/mxnet,zhreshold/mxnet,ZihengJiang/mxnet,precedenceguo/mxnet,tlby/mxnet,stefanhenneking/mxnet,lxn2/mxnet,xcgoner/dist-mxnet,thirdwing/mxnet,danithaca/mxnet,leezu/mxnet,hpi-xnor/BMXNet,kevinthesun/mxnet,reminisce/mxnet,fullfanta/mxnet,crazy-cat/incubator-mxnet,madjam/mxnet,coder-james/mxnet,szha/mxnet,formath/mxnet,ptrendx/mxnet,mbaijal/incubator-mxnet,likelyzhao/mxnet,stefanhenneking/mxnet,ShownX/incubator-mxnet,vikingMei/mxnet,arikpoz/mxnet,DickJC123/mxnet,zhreshold/mxnet,yuruofeifei/mxnet,sergeykolychev/mxnet,arikpoz/mxnet,jermainewang/mxnet,ShownX/incubator-mxnet,hpi-xnor/BMXNet,Ldpe2G/mxnet,ForkedReposBak/mxnet,coder-james/mxnet,sergeykolychev/mxnet,hotpxl/mxnet,navrasio/mxnet,likelyzhao/mxnet,tornadomeet/mxnet,dmlc/mxnet,jermainewang/mxnet,wangyum/mxnet,hotpxl/mxnet,kkk669/mxnet,Prasad9/incubator-mxnet,CodingCat/mxnet,larroy/mxnet,Mega-DatA-Lab/mxnet,indhub/mxnet,nicklhy/mxnet,yajiedesign/mxnet,Guneet-Dhillon/mxnet,hesseltuinhof/mxnet,hesseltuinhof/mxnet,precedenceguo/mxnet,Northrend/mxnet,Ldpe2G/mxnet,ForkedReposBak/mxnet,stefanhenneking/mxnet,apaleyes/mxnet,antoan2/incubator-mxnet,rishita/mxnet,pluskid/mxnet,vikingMei/mxnet,coder-james/mxnet,jamesliu/mxnet,precedenceguo/mxnet,szha/mxnet,madjam/mxnet,Prasad9/incubator-mxnet,thirdwing/mxnet,coder-james/mxnet,nicklhy/mxnet,hotpxl/mxnet,Ldpe2G/mxnet,larroy/mxnet,mbaijal/incubator-mxnet,yuruofeifei/mxnet,lxn2/mxnet,piiswrong/mxnet,thirdwing/mxnet,solin319/incubator-mxnet,saurabh3949/mxnet,sxjscience/mxnet,jennyzhang0215/incubator-mxnet,arank/mxnet,lxn2/mxnet,yuruofeifei/mxnet,Northrend/mxnet,leezu/mxnet,reminisce/mxnet,navrasio/mxnet,ShownX/incubator-mxnet,formath/mxnet,jennyzhang0215/incubator-mxnet,leezu/mxnet,hotpxl/mxnet,sergeykolychev/mxnet,solin319/incubator-mxnet,sxjscience/mxnet,lxn2/mxnet,piiswrong/mxnet,hotpxl/mxnet,madjam/mxnet,LinkHS/incubator-mxnet,tornadomeet/mxnet,rishita/mxnet,DR08/mxnet,ShownX/incubator-mxnet,sxjscience/mxnet,ForkedReposBak/mxnet,Guneet-Dhillon/mxnet,danithaca/mxnet,weleen/mxnet,EvanzzzZ/mxnet,ZihengJiang/mxnet,zhreshold/mxnet,rishita/mxnet,Guneet-Dhillon/mxnet