ITS#8903 - Add option to bind early in ldappasswd

ldappasswd is slightly different from a standard passwd workflow in that it
requests an old password, then a new password, then the old password
again.  This confuses people who are used to the unix passwd tool as
well as people who use password manager.  I've seen quite a few people
who have generated a new password, overwriting the old one, and then
need a password reset because they still need to bind to modify their
password.

This patch adds an option to bind at the beginning of the process so
that you can pass '-E' to ldappasswd and it will bind early in the
process so that the process is the same as the standard passwd.  All it
does is run the bind towards the beginning of the process instead of the
end.

The attached patch file is derived from OpenLDAP Software. All of
the modifications to OpenLDAP Software represented in the following
patch(es) were developed by Randall Mason randall@mason.ch. I have not
assigned rights and/or interest in this work to any party.

I, Randall Mason, hereby place the following modifications to
OpenLDAP Software (and only these modifications) into the public domain.
Hence, these modifications may be freely used and/or redistributed for
any purpose with or without attribution and/or other notice.
