travis: enable go 1.5
travis: enable go 1.5

giantswarm/fleet,bviswana101/fleet,dongsupark/fleet,jonboulle/fleet,dongsupark/fleet,dalbani/fleet,esatterwhite/fleet,coreos/fleet,endocode/fleet,bviswana101/fleet,giantswarm/fleet,endocode/fleet,esatterwhite/fleet,endocode/fleet,improbable-io/fleet,mookjp/fleet,mookjp/fleet,coreos/fleet,dalbani/fleet,paveltiunov/fleet,improbable-io/fleet,dongsupark/fleet,dalbani/fleet,giantswarm/fleet,jonboulle/fleet,improbable-io/fleet,paveltiunov/fleet,coreos/fleet,jonboulle/fleet