Merge r485311 from trunk:

Stop mod_dbd emitting bogus error messages when it's loaded
but not configured.

Submitted by: niq
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@486157 13f79535-47bb-0310-9956-ffa450edef68