Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-next-140119-1' into...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-next-140119-1' into staging

A bunch of fixes for testing:

  - Various Travis updates
  - "stable" SID snapshot for docker
  - avoid :latest docker tags
  - g_usleep fix for some tests

# gpg: Signature made Mon 14 Jan 2019 14:59:35 GMT
# gpg:                using RSA key FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>"
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-next-140119-1: (21 commits)
  Revert "tests: Disable qht-bench parallel test when using gprof"
  tests: use g_usleep instead of rem = sleep(time)
  tests/docker: remove SID_AGE test hack
  tests/docker: update our Travis image
  travis: bump to Xenial baseline
  docker: Use a stable snapshot for Debian Sid
  travis: remove matrix settings that duplicate global settings
  travis: run tests in verbose mode
  travis: stop using container based envs
  travis: stop redefining the script commands
  travis: use homebrew addon for MacOSX
  travis: don't clone git submodules upfront
  travis: standardize the syntax used for env variables
  travis: define all the build matrix entries in one place
  travis: add whitespace between each major section & matrix entry
  tests: use in-place sed magic for enabling deb-src in travis image
  tests: update Fedora i386 cross image to Fedora 29
  tests: update Fedora dockerfile to use Fedora 29
  tests: remove obsolete 'debian' dockerfile
  tests: run ldconfig after installing extra software
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>