Fix crash in mod_log_config when logging

request end time for a failed request
(LogFormat contains %{end}t).

The request_config for mod_log_config might
not be initialized.

PR 54828.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1467765 13f79535-47bb-0310-9956-ffa450edef68