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>