cmd/tip: add a cert cache, clean up Kubernetes config, use update-deps

Fixes expired cert issue too, either by virtue of newer autocert, or
that we're no longer hitting some LetsEncrypt rate limit.

But we have a cache now at least, so we should be nicer to LetsEncrypt
when the process dies. I did see some process crashes (old?) in the
logs. So maybe we were crashing and re-hitting LE often.

Verified that the cert now expires:
    Sunday, October 29, 2017 at 9:57:00 PM Pacific
and that it's cached in GCS.

Fixes golang/go#21251

Change-Id: I3def551ae8eef5df0ec7c51927c4d4bb52cd7a6a
Reviewed-on: https://go-review.googlesource.com/52390
Reviewed-by: Chris Broadfoot <cbro@golang.org>
Reviewed-by: Jessie Frazelle <me@jessfraz.com>
Run-TryBot: Jessie Frazelle <me@jessfraz.com>
4 files changed