We have been having issues with making builds reproducible, especially
with the `.note.go.buildid` ELF section. One tip from a golang issue was
to set `-ldflags=-buildid=` which seems to work well. You can confirm
that the buildid is set to empty by inspecting the binaries with the go
command example `go tool buildid _output/local/go/bin/kubectl`
Signed-off-by: Davanum Srinivas <davanum@gmail.com>