[MINOR] proxy: add a list to hold future layer 4 rules

This list will be evaluated right after the accept() call.
diff --git a/include/types/proxy.h b/include/types/proxy.h
index 3ac80d8..0c1ca76 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -182,6 +182,7 @@
 	struct {                                /* TCP request processing */
 		unsigned int inspect_delay;     /* inspection delay */
 		struct list inspect_rules;      /* inspection rules */
+		struct list l4_rules;           /* layer4 rules */
 	} tcp_req;
 	int acl_requires;                       /* Elements required to satisfy all ACLs (ACL_USE_*) */
 	struct server *srv, defsrv;		/* known servers; default server configuration */