Eliminate DoS attack when a bad URI path contains what

looks like a printf format escape.  This was caused by allowing
tainted data from the network to be placed within the format string
of a call to ap_log_rerror.

PR: Reported by Remco van de Meent <rvdmeent@xs4all.nl>, Studenten Net Twente
Obtained from:
Submitted by:	Marc Slemko
Reviewed by:	Roy Fielding


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82332 13f79535-47bb-0310-9956-ffa450edef68