The previous commit introduced a new interface for the auth modules. This
commit simply updates the other auth modules to use the new interface.
The basic auth module is also updated so that if a user has a shadow
password entry indicated, but the shadow entry cannot be found, an error
is logged rather than silently succeeding.
The BSD authentication module is also updated to allow it to be
compiled on a Linux system for basic testing.
matt335672
d2a5fcdcd8