SECURITY: CVE-2013-5704 (cve.mitre.org)

core: HTTP trailers could be used to replace HTTP headers
late during request processing, potentially undoing or
otherwise confusing modules that examined or modified
request headers earlier.  Adds "MergeTrailers" directive to restore
legacy behavior.

Submitted by: Edward Lu, Yann Ylavic, Joe Orton, Eric Covener
Backports: r1610814
Reviewed by: covener, wrowe, ylavic



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1619884 13f79535-47bb-0310-9956-ffa450edef68