BF: give a custom prefix to a tempfile and close it upon tearDown in ExecuteActions tests
DOC: minor wording fix
BF(?): stop/join notifier only if defined

Somehow on that elderly squeeze Debian sparc box, I got error that self.__notifier
was not defined.  So first I did define it now in the constructor, but mystery remains
how come it was not defined -- wasn"t run() then run (where it is defined)?

Anyways -- conditioning on it being defined might be safer may be?
Not sure (need to go to sleep) if with this change but on this box I also run from time
to time either into stalling of fail2ban-testcases and refusing to exit normally or

======================================================================
ERROR: test_move_into_file_after_removed (testcases.filtertestcase.MonitorFailures<FilterPyinotify>(/tmp/monitorfailures_FilterPyinotifypcHmMJfail2ban))
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/yoh/deb/gits/fail2ban/testcases/filtertestcase.py", line 473, in tearDown
    self.filter.stop()
  File "/home/yoh/deb/gits/fail2ban/server/filterpyinotify.py", line 196, in stop
    self.__notifier.stop()
  File "/usr/lib/pymodules/python2.6/pyinotify.py", line 1315, in stop
    threading.Thread.join(self)
  File "/usr/lib/python2.6/threading.py", line 633, in join
    raise RuntimeError("cannot join thread before it is started")
RuntimeError: cannot join thread before it is started

that is with pyinotify 0.8.9-1 so could quite be "related" to its age.
ENH: use unique filename in LogFileFilterPoll on every setUp call
BF: overcome problem with failed *_movefile test if file gets properly closed

Discussion is in the comments on 7260403fdd41b74335a0a71579df3df5cae6c6ba
and fix consists of skipping first 3 lines while creating a "new" log file.
This should be sufficient to make fail2ban detect "log rotation" and thus
function properly
DOC: changelog entry on leaky file descriptors
Merge pull request #694 from yarikoptic/bf/fix_move_test

a collection of fixes, including the one log rotation detection which "broke travis"