userIdentity in LDAP Password Modify

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

Note that this field may or may not be a DN.  It may be just
a simple user name, e.g. "bob", or it may even be an LDAP
authzid (e.g., u:bob or dn:cn=bob,dc=example,dc=com).

Hence, we should do, much like we do for SASL authzids, apply
appropriate mappings to produce the internal DN representing
the user.

Additionally, the user's password may or may not be held in the
directory.  It could be held in sasldb or other external store.

Anyways, this message is intended just to enumerate some of the
things which should find their way onto the TODO list.

Kurt