travis: download dotcloud/tar before running godep restore
travis: download dotcloud/tar before running godep restore

See kr/godep#42 for more details.

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