Merge fix for CVE-2011-3607:

      Fix integer overflow in ap_pregsub()

Trunk fix: r1198940
Submitted by: Stefan Fritsch, Greg Ames
Reviewed by: Stefan Fritsch, Greg Ames, Eric Covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1227280 13f79535-47bb-0310-9956-ffa450edef68