We need to set r->handler to indicate that we'll be handling the

We need to set r->handler to indicate that we'll be handling the
request. Otherwise, other modules may attempt to do "funny stuff" with
the request (specifically: mod_dir will map /some/path/ into an
index.html document if found).

This reinstalls a fixups hook to set the r->handler value. Most of the
checks in the dav_handler() function are now moved to the fixups hook.
We just don't bother to set the handler unless all conditions are met.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96853 13f79535-47bb-0310-9956-ffa450edef68