[travis-ci] use only ruby-2.1.0
[travis-ci] use only ruby-2.1.0

iBenza/rendezvous,maripiyoko/rendezvous,soramugi/rendezvous,ueokande/rendezvous,tadyjp/rendezvous,takesato/rendezvous,iBenza/rendezvous,takesato/rendezvous,maripiyoko/rendezvous,soramugi/rendezvous,ueokande/rendezvous,ueokande/rendezvous,takesato/rendezvous,tadyjp/rendezvous,maripiyoko/rendezvous,maripiyoko/rendezvous,soramugi/rendezvous,maripiyoko/rendezvous,soramugi/rendezvous,soramugi/rendezvous,tadyjp/rendezvous,iBenza/rendezvous,iBenza/rendezvous,ueokande/rendezvous,takesato/rendezvous,takesato/rendezvous,iBenza/rendezvous,tadyjp/rendezvous,tadyjp/rendezvous,ueokande/rendezvous