Second stab at Volker's 'make shadow passwords work' patch.

Second stab at Volker's 'make shadow passwords work' patch.

Basicly, the password and the salt must be taken from the same place in both
passwd and shadow based systems.  Taking salt from one, and password from the
other just doesn't work.

So pull them from passwd, then overwrite them if need be.

When modifying this file, watch the #ifdef hell - as vl found out, some
variables are globals - but only with #ifndef WITH_PAM, and the code jumps all
over the place with the password cracker.

Getting double-reviews of any change to this file highly advised, it is one of
our most system-specifc areas of code.

(So now I get to take the blame for this one... :-)

Andrew Bartlett
(This used to be commit f39f167900db3f06ec3c52c3ddf61e8bf3d57f56)