check_ntpmon.py tries to divide by 0 if there is no peer in sync

[Junien F]

$ sudo ntpq -pn
     remote refid st t when poll reach delay offset jitter
==============================================================================
 10.35.60.40 .INIT. 16 u 505 1024 0 0.000 0.000 0.000
 10.35.60.41 .INIT. 16 u 471 1024 0 0.000 0.000 0.000

$ sudo /usr/local/lib/nagios/plugins/check_ntpmon.py --check sync
Traceback (most recent call last):
  File "/usr/local/lib/nagios/plugins/check_ntpmon.py", line 360, in <module>
    main()
  File "/usr/local/lib/nagios/plugins/check_ntpmon.py", line 337, in main
    ntp = NTPPeers(lines, checkntpmon)
  File "/usr/local/lib/nagios/plugins/check_ntpmon.py", line 214, in __init__
    self.ntpdata['reachability'] = float(self.ntpdata['totalreach']) * 100 / self.ntpdata['peers'] / 8
ZeroDivisionError: float division by zero

[Nick Moffitt (nick-moffitt)]

We've got a float to start with, so we could probably just add sys.float_info.epsilon to that peers number.

[Paul Gear (paulgear)]

Committed fixed version of check_ntpmon.py to upstream repo (https://github.com/paulgear/ntpmon). The update includes new tests which ensure that the demo data (including this example, newly-added) is parsed correctly.