Merge r1619438 from trunk:

apr_crypto_get_driver(): Fix invalid storage reference
on error path.

Submitted by: Philip Martin <philip.martin wandisco.com>
Reviewed by: trawick


git-svn-id: https://svn.apache.org/repos/asf/apr/apr-util/branches/1.5.x@1619442 13f79535-47bb-0310-9956-ffa450edef68