MEDIUM: acl: replace acl_expr with args in acl fetch_* functions

Having the args everywhere will make it easier to share fetch functions
between patterns and ACLs. The only place where we could have needed
the expr was in the http_prefetch function which can do well without.
diff --git a/src/protocols.c b/src/protocols.c
index 52ddbcc..8a95c2d 100644
--- a/src/protocols.c
+++ b/src/protocols.c
@@ -326,7 +326,7 @@
 /* set temp integer to the number of connexions to the same listening socket */
 static int
 acl_fetch_dconn(struct proxy *px, struct session *l4, void *l7, int dir,
-                struct acl_expr *expr, struct sample *smp)
+                const struct arg *args, struct sample *smp)
 {
 	smp->type = SMP_T_UINT;
 	smp->data.uint = l4->listener->nbconn;
@@ -336,7 +336,7 @@
 /* set temp integer to the id of the socket (listener) */
 static int
 acl_fetch_so_id(struct proxy *px, struct session *l4, void *l7, int dir,
-                struct acl_expr *expr, struct sample *smp)
+                const struct arg *args, struct sample *smp)
 {
 	smp->type = SMP_T_UINT;
 	smp->data.uint = l4->listener->luid;