ENH: Nagios filter

Sample log entry from /var/log/messages for a denied access to the nrpe2 (Nagios Remote Plugin Executor) daemon
ENH: Nagios filter

Sample log for the first failregex is available in the testcases. No example available for the IPv6 denial yet.
ENH: Nagios filter

added typical configuration settings for the nagios filter
ENH: Nagios filter

new filter Nagios added
removing a dot (typo)

The dot at the ignoregex did not belong there. Somehow it was added during the copying and pasting. Thanks for reporting it, I did not see it. Otherwise, empty ignoregexes are in all filters, and if they are missing, fail2ban client shows warnings when starting the filter, which I prefer avoiding.
date fix

sorry, need to get some glasses
removing the second failregex

The second failregex was supposed to catch an error concerning an ACL denial over IPv6, but this message is no more generated by the nrpe version (v2.15) that introduced the IPv6 support, so the first failregex seems to be sufficient.
removing ignoreip at [nagios]

I removed the ignoreip setting from the nagios section. As pointed out, it is redundant here. Nagios server, under normal circumstances should not trigger any access errors, and would be included in the global ignoreips anyway.
Merge pull request #603 from truxoft/master

ENH: Nagios filter