Avoid setting HTTP_PROXY to undefined
Avoid setting HTTP_PROXY to undefined

mbrukman/tilemill,tizzybec/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,fxtentacle/tilemill,tizzybec/tilemill,florianf/tileoven,nyimbi/tilemill,mbrukman/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,MappingKat/tilemill,Zhao-Qi/tilemill,Zhao-Qi/tilemill,paulovieira/tilemill-clima,tilemill-project/tilemill,paulovieira/tilemill-clima,mbrukman/tilemill,paulovieira/tilemill-clima,paulovieira/tilemill-clima,MappingKat/tilemill,Zhao-Qi/tilemill,nyimbi/tilemill,fxtentacle/tilemill,fxtentacle/tilemill,Zhao-Qi/tilemill,mbrukman/tilemill,tilemill-project/tilemill,paulovieira/tilemill-clima,florianf/tileoven,Teino1978-Corp/Teino1978-Corp-tilemill,MappingKat/tilemill,tilemill-project/tilemill,nyimbi/tilemill,nyimbi/tilemill,tizzybec/tilemill,tizzybec/tilemill,MappingKat/tilemill,florianf/tileoven,MappingKat/tilemill,mbrukman/tilemill,Teino1978-Corp/Teino1978-Corp-tilemill,fxtentacle/tilemill,Zhao-Qi/tilemill,fxtentacle/tilemill,tizzybec/tilemill,nyimbi/tilemill