APR-ize the resolver logic in mod_unique_id. This fixes a bug

in logging the error from a failed DNS lookup.

Note: For a funky error scenario to work right (huge host name),
this requires a tweak to apr_gethostname() which I have not yet
committed.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92032 13f79535-47bb-0310-9956-ffa450edef68