Fix warnings during integration tests

[hmpf]

tests/integration/statemondb_test.py::test_get_checkers_does_not_raise
  /source/python/nav/statemon/db.py:76: DeprecationWarning: setDaemon() is deprecated, set the daemon attribute instead
    self.setDaemon(1)

tests/integration/watchdog_test.py::test_get_status_cache_does_not_raise
  /source/.tox/integration-py310-django32/lib/python3.10/site-packages/django/core/cache/backends/filebased.py:36: RuntimeWarning: Pickled model instance's Django version 3.2.23 does not match the current version 3.2.24.
    return pickle.loads(zlib.decompress(f.read()))

tests/integration/ipdevpoll/pool_test.py: 13 warnings
tests/integration/ipdevpoll/plugins/juniper_alarm_test.py: 75 warnings
tests/integration/ipdevpoll/plugins/snmpcheck_test.py: 7 warnings
  /source/python/nav/ipdevpoll/jobs.py:527: DeprecationWarning: isSet() is deprecated, use is_set() instead
    if self.cancelled.isSet():

tests/integration/ipdevpoll/pool_test.py: 2 warnings
tests/integration/ipdevpoll/plugins/juniper_alarm_test.py: 12 warnings
tests/integration/ipdevpoll/plugins/snmpcheck_test.py: 1 warning
  /source/python/nav/ipdevpoll/jobs.py:322: DeprecationWarning: isSet() is deprecated, use is_set() instead
    if self.cancelled.isSet():