rngd: Silence initscript when rngd is already started.

When a hardware random number generator is found by udev
it will start rngd automatically which is what we also do
by default in the initialisation sequence of the system
(e.g. for RDRAND).
The user will then see an error message that rngd has
already been started which was confusing.
Revert "General-functions.pl: rewrite getnetworkip without inet_aton"

This reverts commit 1be398ae381d4d0cdbd50272bff4434121d36f65.

Some users reported some issues with the generated firewall ruleset
with the new function:
  http://forum.ipfire.org/index.php?topic=11124.0
Revert "General-functions.pl: rewrite IpInSubnet replace inet_ntoa"

This reverts commit ab92dc0c84cc6c11f90e753439567d80bac23e2b.

See comment in last commit