Invert calloc(3) argument order.

[araujo]

Summary

Seemed some calloc(3) calls has its arguments inverted,
by the manpage it should be used nitems and size, and not
the oposite.

As I don't really know the intention of the code, would
like a double check from the maintainer.

[trasz]

Looks fine, thanks! Note that those files are duplicated in iscsid(8), so you might also want to fix it there.