docker: use a non conflicting environment variable
docker: use a non conflicting environment variable

dx9/cattle,cjellick/cattle,willseward/cattle,alena1108/cattle,kaos/cattle,willseward/cattle,stresler/cattle,OnePaaS/cattle,Cerfoglg/cattle,prachidamle/cattle,imikushin/cattle,willseward/cattle,cjellick/cattle,OnePaaS/cattle,Cerfoglg/cattle,ubiquityhosting/rancher_cattle,prachidamle/cattle,sonchang/cattle,jimengliu/cattle,gpndata/cattle,gpndata/cattle,sonchang/cattle,kaos/cattle,hibooboo2/cattle,alena1108/cattle,yasker/cattle,cjellick/cattle,gpndata/cattle,rancher/cattle,yasker/cattle,cloudnautique/cattle,cloudnautique/cloud-cattle,stresler/cattle,ubiquityhosting/rancher_cattle,cloudnautique/cattle,wlan0/cattle,imikushin/cattle,cloudnautique/cattle,wlan0/cattle,Cerfoglg/cattle,rancherio/cattle,OnePaaS/cattle,prachidamle/cattle,hibooboo2/cattle,wlan0/cattle,rancher/cattle,dx9/cattle,kaos/cattle,rancher/cattle,vincent99/cattle,dx9/cattle,OnePaaS/cattle,hibooboo2/cattle,alena1108/cattle,cloudnautique/cloud-cattle,vincent99/cattle,dx9/cattle,yasker/cattle,cloudnautique/cloud-cattle,sonchang/cattle,jimengliu/cattle,gpndata/cattle,rancherio/cattle,prachidamle/cattle,imikushin/cattle,cjellick/cattle,stresler/cattle,vincent99/cattle,cloudnautique/cloud-cattle,rancherio/cattle,imikushin/cattle,jimengliu/cattle,ubiquityhosting/rancher_cattle,sonchang/cattle,ubiquityhosting/rancher_cattle,cloudnautique/cattle,willseward/cattle