iptables-save: module loading corrections

1. Ignore the absence of /proc/net/ip_tables_names, which happens
when x_tables.ko is not loaded. This is equivalent to having
x_tables.ko, but no tabe modules, loaded. As such, success should
be returned.

2. Load table when explicitly requested by the -t option. Users might
expect "*foo" etc. to be output when `iptables-save -t foo` is
executed. So do autoload x_tables.ko and the table in this case.

*. Do this for both iptables-save and ip6tables-save, and adjust
the manpages for the new -M (modprobe program location) option that
is introduced.

Based upon a patch by Soren Hansen.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
4 files changed