* Fix If-Match handling:

  - We need to fail if we do NOT match.
  - ETag comparison only makes sense if we have an ETag

PR: 57358
Submitted by: Kunihiko Sakamoto <ksakamoto google.com>
Reviewed by: rpluem


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1646282 13f79535-47bb-0310-9956-ffa450edef68