Merge remote-tracking branch 'remotes/berrange/tags/filemon-next-pull-request' into...

Merge remote-tracking branch 'remotes/berrange/tags/filemon-next-pull-request' into staging

filemon: various fixes / improvements to file monitor for USB MTP

Ensure watch IDs unique within a monitor and avoid integer wraparound
issues when many watches are set & unset over time.

# gpg: Signature made Tue 02 Apr 2019 13:53:40 BST
# gpg:                using RSA key BE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>" [full]
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>" [full]
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/filemon-next-pull-request:
  filemon: fix watch IDs to avoid potential wraparound issues
  filemon: ensure watch IDs are unique to QFileMonitor scope
  tests: refactor file monitor test to make it more understandable

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