mwan3: fix race condition on mwan3 restart

This adjustment of the locks fixes the race condition when a mwan3
hotplug script and a mwan3 command are running at the same time.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
(cherry picked from commit 2dac1bcdc9)

net/mwan3/files/etc/hotplug.d/iface/15-mwan3

@@ -12,19 +12,24 @@ if [ "$ACTION" == "ifup" ]; then
         [ -n "$DEVICE" ] || exit 3
 fi
 
+mwan3_lock "$ACTION" "$INTERFACE"
 config_load mwan3
 config_get_bool enabled globals 'enabled' '0'
-[ ${enabled} -gt 0 ] || exit 0
+[ ${enabled} -gt 0 ] || {
+	mwan3_unlock "$ACTION" "$INTERFACE"
+	exit 0
+}
 
-mwan3_lock "$ACTION" "$INTERFACE"
 mwan3_init
 mwan3_set_connected_iptables
 mwan3_set_custom_ipset
-mwan3_unlock "$ACTION" "$INTERFACE"
 
 config_get enabled $INTERFACE enabled 0
 config_get initial_state $INTERFACE initial_state "online"
-[ "$enabled" == "1" ] || exit 0
+[ "${enabled}" == "1" ] || {
+	mwan3_unlock "$ACTION" "$INTERFACE"
+	exit 0
+}
 
 if [ "$ACTION" == "ifup" ]; then
 	config_get family $INTERFACE family ipv4
@@ -58,7 +63,6 @@ else
 	running=1
 fi
 
-mwan3_lock "$ACTION" "$INTERFACE"
 $LOG notice "Execute "$ACTION" event on interface $INTERFACE (${DEVICE:-unknown})"
 
 case "$ACTION" in