remove go1.5 version limit
remove go1.5 version limit

gorelease/gorelease,gobuild/gorelease,gobuild/gorelease,gobuild/gorelease,gobuild/gobuild,gobuild/gobuild,gobuild/gobuild,gobuild/gobuild,gorelease/gorelease,gorelease/gorelease,gobuild/gorelease,gorelease/gorelease