Merge remote-tracking branch 'remotes/huth/tags/check-20170915' into staging

Some fixes and improvements for various qtests by Eric and me.

# gpg: Signature made Fri 15 Sep 2017 08:37:21 BST
# gpg:                using RSA key 0x2ED9D774FE702DB5
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>"
# gpg:                 aka "Thomas Huth <thuth@redhat.com>"
# gpg:                 aka "Thomas Huth <huth@tuxfamily.org>"
# gpg:                 aka "Thomas Huth <th.huth@posteo.de>"
# Primary key fingerprint: 27B8 8847 EEE0 2501 18F3  EAB9 2ED9 D774 FE70 2DB5

* remotes/huth/tags/check-20170915:
  qtest: Avoid passing raw strings through hmp()
  libqtest: Remove dead qtest_instances variable
  numa-test: Use hmp()
  qtest: Don't perform side effects inside assertion
  test-qga: Kill broken and dead QGA_TEST_SIDE_EFFECTING code
  tests: Fix broken ivshmem-server-msi/-irq tests
  tests/libqtest: Use a proper error message if QTEST_QEMU_BINARY is missing
  tests/test-hmp: Remove puv3 and tricore_testboard from the blacklist
  tests: Introduce generic device hot-plug/hot-unplug functions

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