Improve HTTPD24_ERRORLOG parsing of proxy errors

[smokris]

Problem

Currently, HTTPD24_ERRORLOG fails to correctly parse this message:

[Fri Sep 13 20:16:16.614584 2024] [proxy_fcgi:error] [pid 74738:tid 74765] (70008)Partial results are valid but processing is incomplete: [client 203.0.113.1:0] AH01075: Error dispatching request to : (reading input brigade)

Analysis

1. This clause appears to have a stray question mark:

   %{POSINT:[apache][error][proxy][error][code]?}

2. This clause only allows ports 1 and greater (whereas the above log message indicates port 0):

   %{POSINT:[source][port]:int}

Proposed change

1. Remove stray question mark
2. Change POSINT to NONNEGINT