Make NDBM file suffix determination for mod_rewrite more accurate, i.e.

use `.db' instead of `.pag' not only for FreeBSD, but also when
the NDBM library looks like Berkeley-DB based.

Submitted by: Ralf S. Engelschall
PR: 3773


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82720 13f79535-47bb-0310-9956-ffa450edef68