fix panic when passing empty environment
fix panic when passing empty environment

Docker-DCO-1.1-Signed-off-by: Sridhar Ratnakumar <github@srid.name> (github: srid)

rajasec/runc,cxxly/runc,kolyshkin/runc,mrunalp/libcontainer,ZJU-SEL/libcontainer,BrickXu/libcontainer,jwuwork/runc,axsh/runc,ZJU-SEL/runc,zhangyancoder/libcontainer,zenlinTechnofreak/runc,hxfeng/runc,marcosnils/runc,InformatiQ/runc,subuser-security/runc,ZJU-SEL/libcontainer,runcom/runc,boucher/runc,subuser-security/runc,Microsoft/libcontainer,zenlinTechnofreak/runc,sunyuan3/runc,rootfs/runc,runcom/runc,whuwxl/libcontainer,rhatdan/runc,crosbymichael/runc,shakamunyi/libcontainer,meihuabo/runc,laijs/runc,runcom/libcontainer,nkwilson/runc,ycaihua/libcontainer,han-wang/runc,Microsoft/libcontainer,chenchun/runc,ycaihua/runc,rootfs/runc,w4ngyi/libcontainer,HuKeping/runc,ekuric/runc,haijunTan/runc,ChengTiesheng/runc,dqminh/libcontainer,kimh/runc,wking/runc,avagin/runc,tangkun75/libcontainer,meihuabo/runc,liuwharton/runc,haijunTan/runc,stefanberger/runc,willmtemple/runc,adrianreber/runc,wcwxyz/runc,clnperez/runc,shenxiaochen/libcontainer,opencontainers/runc,mheon/libcontainer,docker/runc,LK4D4/runc,rhatdan/libcontainer,mikebrow/runc,aidanhs/runc,rhatdan/libcontainer,inatatsu/runc,keloyang/libcontainer,ycaihua/libcontainer,BrickXu/libcontainer,keloyang/runc,estesp/runc,unclejack/libcontainer,shakamunyi/libcontainer,markllama/runc,axsh/runc,LTD-Beget/libcontainer,intfrr/runc,boucher/libcontainer,maxamillion/runc,willmtemple/runc,runcom/runc,dqminh/libcontainer,clnperez/runc,justincormack/runc,unclejack/libcontainer,avagin/libcontainer,jhowardmsft/runc,wangkirin/runc,estesp/runc,SaiedKazemi/libcontainer-criu,subuser-security/runc,YujiOshima/runc,booyaa/runc,Mashimiao/libcontainer,rajasec/runc,w4ngyi/libcontainer,milosgajdos83/libcontainer-milosgajdos83,meihuabo/runc,calavera/runc,keloyang/libcontainer,milosgajdos83/libcontainer-milosgajdos83,calavera/runc,kolyshkin/runc,estesp/libcontainer,mheon/runc,BrickXu/libcontainer,keloyang/runc,HuKeping/runc,mheon/libcontainer,dqminh/runc,ddnbgroup/runc,mikebrow/runc,talwai/runc,whuwxl/libcontainer,mrunalp/runc,runcom/libcontainer,icecrime/libcontainer,avagin/runc,booyaa/runc,haijunTan/runc,maxamillion/runc,whuwxl/libcontainer,hqhq/runc,coolljt0725/runc,YujiOshima/runc,jwuwork/runc,balajibr/runc,sunyuan3/runc,aidanhs/runc,YujiOshima/runc,whosthatknocking/runc,fabiokung/runc,lizf-os/runc,cxxly/runc,dieface/runc,jhjeong-kr/runc,crosbymichael/runc,xiaochenshen/runc,whosthatknocking/runc,hxfeng/runc,ddnbgroup/runc,keloyang/libcontainer,Microsoft/libcontainer,rhatdan/runc,jhowardmsft/runc,runcom/libcontainer,InformatiQ/runc,cloudfoundry-incubator/runc,dqminh/runc,dqminh/runc,Mashimiao/libcontainer,sallyom/runc,opencontainers/runc,boucher/libcontainer,balajibr/runc,mYmNeo/runc,willmtemple/runc,dieface/runc,HardikDR/runc,talwai/runc,ChengTiesheng/runc,navidshaikh/runc,coolljt0725/runc,carlye566/runc,ZJU-SEL/runc,LK4D4/runc,ekuric/runc,gitido/runc,LTD-Beget/libcontainer,navidshaikh/runc,icecrime/libcontainer,stefanberger/runc,shenxiaochen/libcontainer,HardikDR/runc,marcosnils/runc,cloudfoundry-incubator/runc,opencontainers/runc,intfrr/runc,hxfeng/runc,crosbymichael/libcontainer,sallyom/runc,stefanberger/runc,abduld/runc,vbatts/runc,jhjeong-kr/runc,whosthatknocking/runc,sallyom/runc,xiaochenshen/runc,cyphar/runc,albertoleal/runc,aidanhs/runc,gwoo/runc,adrianreber/runc,hqhq/runc,intfrr/runc,WeiZhang555/runc,axsh/runc,docker/libcontainer,vbatts/runc,kimh/runc,boucher/libcontainer,rsampaio/runc,cloudfoundry-incubator/runc,avagin/runc,ChengTiesheng/runc,laijs/runc,hqhq/libcontainer,rhatdan/libcontainer,wangkirin/runc,shishir-a412ed/runc,mapk0y/runc,zhangyancoder/libcontainer,hqhq/libcontainer,thaJeztah/libcontainer,wcwxyz/runc,thaJeztah/libcontainer,nkwilson/runc,rajasec/runc,mYmNeo/runc,LTD-Beget/libcontainer,shishir-a412ed/runc,mapk0y/runc,hqhq/libcontainer,inatatsu/runc,kolyshkin/runc,estesp/libcontainer,liuwharton/runc,mheon/libcontainer,albertoleal/runc,cxxly/runc,kolyshkin/runc,wcwxyz/runc,docker/libcontainer,mrunalp/runc,crosbymichael/libcontainer,lizf-os/runc,calavera/runc,ycaihua/libcontainer,rsampaio/runc,vbatts/runc,ZJU-SEL/libcontainer,markllama/runc,keloyang/libcontainer,jhowardmsft/runc,lizf-os/runc,Mashimiao/libcontainer,booyaa/runc,mikebrow/runc,justincormack/runc,estesp/libcontainer,docker/runc,WeiZhang555/runc,carlye566/runc,albertoleal/runc,wking/runc,shishir-a412ed/runc,abduld/runc,liuwharton/runc,mrunalp/libcontainer,sunyuan3/runc,mheon/runc,opencontainers/runc,LK4D4/runc,gitido/runc,zhangyancoder/libcontainer,SaiedKazemi/libcontainer-criu,wking/runc,boucher/runc,dqminh/runc,laijs/runc,mrunalp/libcontainer,HardikDR/runc,mapk0y/runc,keloyang/runc,jhjeong-kr/runc,HuKeping/runc,crosbymichael/libcontainer,wangkirin/runc,thaJeztah/libcontainer,clnperez/runc,markllama/runc,icecrime/libcontainer,fabiokung/runc,han-wang/runc,WeiZhang555/runc,docker/libcontainer,hqhq/runc,nkwilson/runc,navidshaikh/runc,ddnbgroup/runc,maxamillion/runc,fabiokung/runc,balajibr/runc,SaiedKazemi/libcontainer-criu,zenlinTechnofreak/runc,avagin/libcontainer,avagin/libcontainer,rsampaio/runc,justincormack/runc,dieface/runc,dqminh/libcontainer,kimh/runc,xiaochenshen/runc,cyphar/runc,chenchun/runc,tangkun75/libcontainer,InformatiQ/runc,ycaihua/runc,ZJU-SEL/runc,inatatsu/runc,ycaihua/runc,shenxiaochen/libcontainer,jwuwork/runc,mYmNeo/runc,rhatdan/runc,mheon/runc,crosbymichael/runc,gitido/runc,docker/runc,chenchun/runc,shakamunyi/libcontainer,coolljt0725/runc,han-wang/runc,boucher/runc,marcosnils/runc,ekuric/runc,talwai/runc,rootfs/runc,abduld/runc,cyphar/runc,w4ngyi/libcontainer,tangkun75/libcontainer,unclejack/libcontainer,adrianreber/runc,carlye566/runc,rhatdan/runc,mrunalp/runc,estesp/runc