net/mwan3: fix /var/state issue in 14-mwan3 hotplug

Use common function to toggle ip address in /var/state/mwan3.
Change also to use toggle function and not set function. If ip address
is often changed every change is saved to /var/state/mwan3.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

net/mwan3/files/etc/hotplug.d/iface/14-mwan3

@@ -22,7 +22,7 @@ config_get local_source globals local_source 'none'
 }
 
 mwan3_lock
-src_ip=$(uci -q -P /var/state get mwan3.globals.src_ip 2>/dev/null)
+src_ip=$(uci_get_state mwan3 globals src_ip)
 [ "${src_ip}" != "" ] && {
 	ip route del default via "${src_ip}" dev lo 1>/dev/null 2>&1
 	ip addr del "${src_ip}/32" dev lo 1>/dev/null 2>&1
@@ -37,7 +37,7 @@ usleep 10000
 	else
 		ip addr add "${src_ip}/32" dev lo
 		ip route add default via "${src_ip}" dev lo
-		uci -q -P /var/state set mwan3.globals.src_ip="${src_ip}"
+		uci_toggle_state mwan3 globals src_ip "${src_ip}"
 	fi
 }
 mwan3_unlock