fixed the text about authentication in crane usage docs
fixed the text about authentication in crane usage docs

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