reason is that these errors will grow to include 'other' things, like
custom error responses, DAV error responses, and so on. They may also
start including 'sub errors' - local langauge explanations of specific
failures. Let's use the httpd.h constants rather than numbers, they
are easier to read.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@90408 13f79535-47bb-0310-9956-ffa450edef68
