net-firewall/iptables: multiple fixes for runscript

net-firewall/iptables: multiple fixes for runscript

- We are now passing iptables "--wait" option to every iptables
  command which needs to aquire a lock. [Bug 501710]

- In addition, "--wait" (IPTABLES_LOCK_WAIT_TIME) and "--wait-interval"
  (IPTABLES_LOCK_WAIT_INTERVAL) is now configurable via
  /etc/conf.d/{iptables,ip6tables}.

- We are now only installing one runscript and now using a symlink
  for the ip6tables runscript.

- Error detection improved/added.

Closes: https://bugs.gentoo.org/501710
Package-Manager: Portage-2.3.52, Repoman-2.3.12
Signed-off-by: Thomas Deutschmann <whissi@gentoo.org>