two s390x fixes for docker

[Michael Hudson-Doyle]

[Impact]
As explained in https://github.com/golang/go/issues/16021#issuecomment-225029684, the s390x port for Go contains two bugs that prevent docker from operating correctly.

[Test Case]
Build the docker, containerd and runc source packages from yakkety, install them "docker run s390x/ubuntu:16.04 echo hi" -- in the failing case this will hang on exit and containerd will be observed to use 100% cpu.
Rebuild all packages that build-depend on golang in xenial.

[Regression potential]
Slight. I believe the Go point releases meet the guidelines described at https://wiki.ubuntu.com/StableReleaseUpdates#New_upstream_microreleases.

[Launchpad Janitor (janitor)]

This bug was fixed in the package golang-1.6 - 1.6.2-0ubuntu5

---------------
golang-1.6 (1.6.2-0ubuntu5) yakkety; urgency=medium

  * cgo and epoll fixes for s390x. (LP: #1591010)

 -- Michael Hudson-Doyle <email address hidden> Fri, 10 Jun 2016 13:02:04 +1200

[Steve Langasek (vorlon)]

Hello Michael, or anyone else affected,

Accepted golang-1.6 into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/golang-1.6/1.6.2-0ubuntu5~16.04 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Michael Hudson-Doyle (mwhudson)]

I built all packages that build-depend on golang or golang-go in https://launchpad.net/~mwhudson/+archive/ubuntu/go162-rebuilds/+packages and 30 odd failed to build but all of the failures match those in -release:

  cadvisor -- fails on arm64, same in -release
  ciborium -- ftbfs on same arches in -release
  consul-migrate -- ftbfs with Go >= 1.6
  docker-registry -- ftbfs on same arches in -release
  gb -- ftbfs on same arches in -release
  go-md2man -- tries to build with gccgo on s390x
  golang-fsnotify -- succeeded on retry
  golang-ginkgo -- fails on arm64, same as -release (flaky tests)
  golang-git2go -- ftbfs (amd64 only), in -release too
  golang-github-armon-go-metrics -- ftbfs (amd64 only), in -release too
  golang-github-armon-gomdb -- ftbfs (amd64 only), in -release too
  golang-github-aws-aws-sdk-go -- ftbfs (amd64 only), in -release too
  golang-github-davecgh-go-spew -- ftbfs (amd64 only), in -release too
  golang-github-eknkc-amber -- tries to build with gccgo on s390x
  golang-github-hashicorp-raft-mdb -- ftbfs (amd64 only), in -release too
  golang-github-hashicorp-serf -- ftbfs on arm64, succeeded on retry
  golang-github-jacobsa-ogletest -- ftbfs with Go >= 1.5
  golang-github-miekg-mmark -- tries to build with gccgo on arm64 & s390x
  golang-github-miekg-pkcs11 -- ftbfs (amd64 only), in -release too
  golang-github-mitchellh-reflectwalk -- ftbfs (amd64 only), in -release too
  golang-github-samalba-dockerclient -- ftbfs (amd64 only), in -release too
  golang-github-yosssi-ace -- tries to build with gccgo on s390x
  golang-gocheck -- ftbfs (amd64 only), in -release too
  golang-goyaml -- ftbfs with Go >= 1.6 (maybe >= 1.5)
  golang-protobuf-extensions -- ftbfs (amd64 only), in -relase too
  golang-rrd -- ftbfs (amd64 only), in -release too
  gopacket -- ftbfs (amd64 only), in -release too
  juju-mongo-tools3.2 -- ftbfs on arm64, flaky test retry hammer eventually worked
  knot-resolver -- depwait on s390x, ppc64el, arm64, same as -release
  libguestfs -- ftbfs everywhere, go related but same as -release
  ngrok -- depwait on s390x, same as -release
  notary -- ftbfs on arm64, same as -release
  pay-service -- ftbfs everywhere, same in as -release
  prometheus -- ftbfs on arm64, actually better than situation in -release (!?)
  prometheus-node-exporter -- ftbfs everywhere, bit wtf, but same as -release
  slt -- depwait on s390x, same as -release

I haven't verified that the fixes I want help with docker 1.11 on ppc64el and s390x yet, will do that next.

[Michael Hudson-Doyle (mwhudson)]

I have now verified that the Go packages in xenial-release build a broken docker and the Go packages in xenial-proposed build a working docker on s390x and ppc64el, so verification-done.

[Launchpad Janitor (janitor)]

This bug was fixed in the package golang-1.6 - 1.6.2-0ubuntu5~16.04

---------------
golang-1.6 (1.6.2-0ubuntu5~16.04) xenial; urgency=medium

  * Backport new upstream release to Xenial to fix epoll on ppc64el and s390x.
    (LP: #1567096, #1591010)

 -- Michael Hudson-Doyle <email address hidden> Fri, 10 Jun 2016 15:34:17 +1200

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for golang-1.6 has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.