Add default directory for file provider.
Add default directory for file provider.

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