Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-next-050719-3' into...

Merge remote-tracking branch 'remotes/stsquad/tags/pull-testing-next-050719-3' into staging

Various testing fixes:

   - tests/vm updates and clean-ups
   - tests/vm serial autobuild on host (-netbsd v3)
   - ensure MacOS builds do "brew update"
   - ensure we test --static user builds
   - fix hyperv compile failure
   - fix missing var warning for OpenBSD (v2)

This brings my testing back to green on all CI services. Please note
the BSD installs will throw out some warnings during the setup phase.
They shouldn't re-occur once the images are built. NetBSD has been
dropped for now given slow install issues.

# gpg: Signature made Fri 05 Jul 2019 11:15:21 BST
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-testing-next-050719-3:
  migration: move port_attr inside CONFIG_LINUX
  target/i386: fix feature check in hyperv-stub.c
  Makefile: Rename the 'vm-test' target as 'vm-help'
  .travis.yml: force a brew update for MacOS builds
  .travis.yml: default the --disable-system build to --static
  tests/vm: ubuntu.i386: apt proxy setup
  tests/vm: fedora autoinstall, using serial console
  tests/vm: freebsd autoinstall, using serial console
  tests/vm: openbsd autoinstall, using serial console
  tests/vm: serial console support helpers
  tests/vm: add vm-boot-{ssh,serial}-<guest> targets
  tests/vm: proper guest shutdown
  tests/vm: run test builds on snapshot
  tests/vm: use ssh with pty unconditionally
  tests/vm: send proxy environment variables over ssh
  tests/vm: add source repos on ubuntu.i386
  tests/vm: pin ubuntu.i386 image
  tests/vm: avoid image presence check and removal
  tests/vm: avoid extra compressed image copy

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