iptables: fix layer7 patch to place the source in extensions/, I doubt it ever worked

SVN-Revision: 24719

package/iptables/patches/002-layer7_2.22.patch

@@ -1,5 +1,5 @@
 --- /dev/null
-+++ b/libxt_layer7.c
++++ b/extensions/libxt_layer7.c
 @@ -0,0 +1,368 @@
 +/* 
 +   Shared library add-on to iptables for layer 7 matching support.