network-hotplug-bridges: Fix logical error in STP_PRIORITY check

Reported-by: Daniel Weismüller <daniel.weismueller@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

config/rootfiles/core/154/filelists/files

@@ -5,6 +5,7 @@ etc/rc.d/init.d/functions
 etc/rc.d/init.d/sshd
 etc/rc.d/init.d/unbound
 etc/rc.d/init.d/wlanclient
+lib/udev/network-hotplug-bridges
 opt/pakfire/lib/functions.sh
 srv/web/ipfire/cgi-bin/country.cgi
 srv/web/ipfire/cgi-bin/credits.cgi

config/udev/network-hotplug-bridges

@@ -87,8 +87,8 @@ STP_PRIORITY="$(get_value "${ZONE}_STP_PRIORITY")"
 case "${MODE}" in
 	bridge)
 		# We need to check if $STP_PRIORITY has a valid value if not set it
-		if [ -n "${STP_PRIORITY}" ]; then
-			STP_PRIORITY=16384;
+		if [ -z "${STP_PRIORITY}" ]; then
+			STP_PRIORITY=16384
 		fi
 
 		ADDRESS="$(get_value "${ZONE}_MACADDR")"