Merge r559804 from trunk:

mod_filter: fix merging of ! and =
PR: 42186 - patch by Issac Goldstand

Submitted by: niq
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@562441 13f79535-47bb-0310-9956-ffa450edef68