Fix a potential segfault if the bind password in the LDAP cache

is NULL.
PR:	26686
Obtained from:
Submitted by:	Jari Ahonen <jah@progress.com>
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@103713 13f79535-47bb-0310-9956-ffa450edef68