Had to add a "pam password change" parameter (defaults to "off") and inlined

Had to add a "pam password change" parameter (defaults to "off") and inlined
the pam password change code to ensure that existing and working password
chat scripts don't break with 2.2.1. PAM password changing has to be explicitly
requested.
Allowed wildcards in pam password change matching (matches password chat
script matching). Had to add const (sorry Tim :-) to ms_fnmatch() to
stop warnings. Don't worry - the const changes are isolated and don't
cause any other warnings :-).
Jeremy.
(This used to be commit 47b4d82536c09bffe3a0d9917fa31d935f1be7d8)