run-config.sh: Removed "mac" (MAC address) variable

It was only used by the availability option. Because availability is not
used anymore, the "mac" variable was removed.

Signed-off-by: Erik Alexandre Pucci <eap08@c3sl.ufpr.br>
Acked-by: Ricardo Tavares de Oliveira <rto07@c3sl.ufpr.br>
Signed-off-by: Danilo K. S. Yorinori <danilok@c3sl.ufpr.br>