http_protocol: Escape request method in 413 error reporting.

Determined to be not generally exploitable, but a flaw in any case.

PR: 44014
Submitted by: Victor Stinner <victor.stinner inl.fr>




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@600645 13f79535-47bb-0310-9956-ffa450edef68