Forward port: Escape special characters (especially control
characters) in mod_log_config to make a clear distinction between
client-supplied strings (with special characters) and server-side
strings. This was already introduced in version 1.3.25.

Obtained from: Patch in 1.3.25-dev by Martin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@98912 13f79535-47bb-0310-9956-ffa450edef68