firewall: - defer firewall start until the first interface is brought up by hotplug...

firewall: - defer firewall start until the first interface is brought up by hotplug, fixes race conditions on slow devices - create a file lock during firewall start and wait for it in hotplug events, prevents race conditions between start and addif - start firewall actions in background from hotplug handler since the firewall itself fires further hotplug events which results in a deadlock if not forked off - get loaded state direcly from the uci binary since updated value is not recognized by config_get after uci_set_state - bump package revision to r2

SVN-Revision: 21486