Merge remote-tracking branch 'remotes/huth-gitlab/tags/pull-request-2019-08-15' into staging

- Fix for ctrl queue in the virtio-net QOS driver
- Improve Valgrind reports in the tests that use the null-co driver
- Get rid of global_qtest related code in libqtest and libqos

# gpg: Signature made Thu 15 Aug 2019 18:28:16 BST
# gpg:                using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5
# gpg:                issuer "thuth@redhat.com"
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full]
# gpg:                 aka "Thomas Huth <thuth@redhat.com>" [full]
# gpg:                 aka "Thomas Huth <huth@tuxfamily.org>" [full]
# gpg:                 aka "Thomas Huth <th.huth@posteo.de>" [unknown]
# Primary key fingerprint: 27B8 8847 EEE0 2501 18F3  EAB9 2ED9 D774 FE70 2DB5

* remotes/huth-gitlab/tags/pull-request-2019-08-15:
  tests/libqtest: Make qmp_assert_success() independent from global_qtest
  tests/libqtest: Make qtest_qmp_device_add/del independent from global_qtest
  tests/libqtest: Clean up qtest_cb_for_every_machine() wrt global_qtest
  tests/libqtest: Remove unused function hmp()
  tests/libqos: Make virtio-pci code independent from global_qtest
  tests/libqos: Make generic virtio code independent from global_qtest
  tests: Set read-zeroes on for null-co driver
  libqos: Account for the ctrl queue in virtio-net
  qtest: Rename qtest.c:qtest_init()

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