firewall: make sure that -m mac is used with --mac-source, follow up to r27508

SVN-Revision: 27519

package/firewall/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=firewall
 
 PKG_VERSION:=2
-PKG_RELEASE:=29
+PKG_RELEASE:=30
 
 include $(INCLUDE_DIR)/package.mk
 

package/firewall/files/lib/core_redirect.sh

@@ -109,7 +109,7 @@ fw_load_redirect() {
 				$srcaddr ${destaddr:--m conntrack --ctstate DNAT} \
 				$pr \
 				$srcports $destports \
-				$sm \
+				${sm:+-m mac $sm} \
 				$redirect_extra \
 			}
 		done