Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Miscellaenous bugfixes, including crash fixes from Alexey, Peter M. and
Thomas.

# gpg: Signature made Mon 26 Mar 2018 13:37:38 BST
# gpg:                using RSA key BFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream:
  qemu-pr-helper: Actually allow users to specify pidfile
  chardev/char-fe: Allow NULL chardev in qemu_chr_fe_init()
  iothread: fix breakage on windows
  scsi: turn "is this a SCSI device?" into a conditional hint
  chardev-socket: remove useless if
  tcg: Really fix cpu_io_recompile
  vhost-user-test: add back memfd check
  vhost-user-test: do not hang if chardev creation failed
  scripts/device-crash-test: Remove fixed isapc-with-iommu entry
  hw/audio: Fix crashes when devices are used on ISA bus without DMA
  fdc: Exit if ISA controller does not support DMA
  hw/net/can: Fix segfaults when using the devices without bus
  WHPX improve vcpu_post_run perf
  WHPX fix WHvSetPartitionProperty in PropertyCode
  WHPX fix WHvGetCapability out WrittenSizeInBytes
  scripts/get_maintainer.pl: Print proper error message for missing $file

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