etc/tsuru-docker.conf: removing default index
etc/tsuru-docker.conf: removing default index

This would make tsuru push all applications images by default to the
docker public index, which is really no good.

Thanks to @dgryski.

firebitsbr/tsuru,4eek/tsuru,ggarnier/tsuru,gwmoura/tsuru,RichardKnop/tsuru,guilhermebr/tsuru,cgvarela/tsuru,gciotta/tsuru,ggarnier/tsuru,ArxdSilva/tsuru,cezarsa/tsuru,gwmoura/tsuru,hugoantunes/tsuru,RichardKnop/tsuru,mderaldo/tsuru,guilhermebr/tsuru,jblancett/tsuru,firebitsbr/tsuru,hcxiong/tsuru,tsuru/tsuru,cgvarela/tsuru,tsuru/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,Endika/tsuru,Endika/tsuru,jblancett/tsuru,cgvarela/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,mderaldo/tsuru,kgrvamsi/tsuru,RichardKnop/tsuru,tuxmonteiro/tsuru,kgrvamsi/tsuru,gciotta/tsuru,tsuru/tsuru,kgrvamsi/tsuru,hcxiong/tsuru,mderaldo/tsuru,hcxiong/tsuru,4eek/tsuru,jblancett/tsuru,gwmoura/tsuru,firebitsbr/tsuru,tuxmonteiro/tsuru,tsuru/tsuru,4eek/tsuru,hugoantunes/tsuru,guilhermebr/tsuru,gciotta/tsuru,cezarsa/tsuru,cezarsa/tsuru,ggarnier/tsuru,tuxmonteiro/tsuru,ArxdSilva/tsuru,Endika/tsuru,cezarsa/tsuru