add the ability to specify the dbm type (e.g., gdbm, ndbm) for

dbm rewrite maps

use dbm:filename for the default type

use dbm=TYPE:filename for a non-default type


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96493 13f79535-47bb-0310-9956-ffa450edef68