Merge r1556428 from trunk:

      SECURITY: CVE-2013-6438 (cve.mitre.org)
mod_dav: Keep track of length of cdata properly when removing leading spaces.

* modules/dav/main/util.c
  (dav_xml_get_cdata): reduce len variable when increasing cdata pointer.

Submitted by: Amin Tora <Amin.Tora neustar.biz>

Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1556816 13f79535-47bb-0310-9956-ffa450edef68