Merge r1609938 from trunk:

core: Include any error notes set by modules in the canned error
response for 403 errors.

Submitted by: trawick
Reviewed by: minfrin, rjung


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1610328 13f79535-47bb-0310-9956-ffa450edef68