generation of manpages.
* man/generate_translations.mak: Added pam/no_pam condition (like
in man/Makefile.am).
* man/Makefile.am, man/generate_translations.mak: Added
gshadow/no_gshadow condition.
* man/gpasswd.1.xml: Use the gshadow/no_gshadow condition to
change the manpage depending on the shadow group support.