Fixed error handling in dbmmanage script.

Submitted by: Andrew McRae <andrew@liquid.com>
Reviewed by: Ralf S. Engelschall
PR: 4973


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@84178 13f79535-47bb-0310-9956-ffa450edef68