"[mod_dav_fs etag handling] should really honor the FileETag setting".

"[mod_dav_fs etag handling] should really honor the FileETag setting".
- It now does.
- Add "Digest" to FileETag directive, allowing a strong ETag to be
  generated using a file digest.
- Add ap_make_etag_ex() and ap_set_etag_fd() to allow full control over
  ETag generation.
- Add concept of "binary notes" to request_rec, allowing packed bit flags
  to be added to a request.
- First binary note - AP_REQUEST_STRONG_ETAG - allows modules to force
  the ETag to a strong ETag to comply with RFC requirements, such as those
  mandated by various WebDAV extensions.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1879285 13f79535-47bb-0310-9956-ffa450edef68