Merge r1527509 from trunk:

mod_dav: set r->status_line in dav_error_response.
It's used as argument in next ap_rvputs call. PR 55426.

Submitted by: jkaluza
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1634519 13f79535-47bb-0310-9956-ffa450edef68