Merge r674000 from trunk:

* Prevent Header edit from processing only the first header it should
  edit and deleting the remaining ones by iterating over all headers
  with the same name.

PR: 45333

Submitted by: rpluem
Reviewed by: rpluem, niq, mturk


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@684100 13f79535-47bb-0310-9956-ffa450edef68