Fix pregsub to check the correct value, and not try and substitute

matches that didn't occur.

Reviewed by: Ralf S. Engelschall, Randy Terbush


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@78337 13f79535-47bb-0310-9956-ffa450edef68