Update Travis to use official Rust support
Update Travis to use official Rust support

efuquen/coreutils,ebfe/coreutils,Shtong/coreutils,filmor/coreutils,hexsel/coreutils,steveklabnik/coreutils,kevgeniy/coreutils,dennis/coreutils,kball/coreutils,silvio/rust-coreutils,efuquen/coreutils,ebfe/coreutils,bundai223/coreutils,uutils/coreutils,mauricio/coreutils,tempbottle/coreutils,steveklabnik/coreutils,retep998/coreutils,keunwoo/coreutils,Shtong/coreutils,jbcrail/coreutils,keunwoo/coreutils,wimh/coreutils,hexsel/coreutils,kwantam/coreutils,Arcterus/coreutils,dbrgn/coreutils,silvio/rust-coreutils,sshling/coreutils,dokaptur/coreutils,Gianbaoluo/coreutils,Heather/coreutils,retep998/coreutils,kevgeniy/coreutils,jbcrail/coreutils,dennis/coreutils,uutils/coreutils,Shir0kamii/coreutils,Heather/coreutils,wimh/coreutils,beni55/coreutils,polapl/coreutils,filmor/coreutils,tempbottle/coreutils,beni55/coreutils,Gianbaoluo/coreutils,samfoo/coreutils,Shir0kamii/coreutils,dbrgn/coreutils,Arcterus/coreutils,uutils/coreutils,bundai223/coreutils,dbrgn/coreutils,mauricio/coreutils,sshling/coreutils,kball/coreutils,samfoo/coreutils,polapl/coreutils,kwantam/coreutils