firewal: update to latest git HEAD

4d0c703 firewall3: Fix some format string problems
8c404ef iptables.c: lock the xtables.lock
c1d3a4d utils: implement fw3_lock_path() & fw3_unlock_path()

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

package/network/config/firewall/Makefile

@@ -13,9 +13,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/firewall3.git
-PKG_SOURCE_DATE:=2019-08-21
-PKG_SOURCE_VERSION:=bf29c1e7e95c00953da9430e4c5144ef2b79a361
-PKG_MIRROR_HASH:=de66fce181893cbd0d90ef89860e618db3e975a0713ecfaaa83b9f657c5beb43
+PKG_SOURCE_DATE:=2019-09-02
+PKG_SOURCE_VERSION:=4d0c703e750cdbaa7d8afc56de05bd1238e3c981
+PKG_MIRROR_HASH:=34f49c13dde5386b7e95be89f5863e89e28fe8e66c4be23f0746b44bbe79df27
 PKG_MAINTAINER:=Jo-Philipp Wich <jo@mein.io>
 PKG_LICENSE:=ISC