[MINOR] acl: provide a reference to the expr to fetch()

The fetch() functions may need to access the full expr to get
their args. Turn the void *arg into a struct acl_expr *expr.
diff --git a/src/proto_http.c b/src/proto_http.c
index 5f991e5..ea199d9 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -5165,7 +5165,8 @@
 }
 
 static int
-acl_fetch_meth(struct proxy *px, struct session *l4, void *l7, int dir, void *arg, struct acl_test *test)
+acl_fetch_meth(struct proxy *px, struct session *l4, void *l7, int dir,
+               struct acl_expr *expr, struct acl_test *test)
 {
 	int meth;
 	struct http_txn *txn = l7;
@@ -5209,7 +5210,8 @@
 }
 
 static int
-acl_fetch_rqver(struct proxy *px, struct session *l4, void *l7, int dir, void *arg, struct acl_test *test)
+acl_fetch_rqver(struct proxy *px, struct session *l4, void *l7, int dir,
+                struct acl_expr *expr, struct acl_test *test)
 {
 	struct http_txn *txn = l7;
 	char *ptr;
@@ -5230,7 +5232,8 @@
 }
 
 static int
-acl_fetch_stver(struct proxy *px, struct session *l4, void *l7, int dir, void *arg, struct acl_test *test)
+acl_fetch_stver(struct proxy *px, struct session *l4, void *l7, int dir,
+                struct acl_expr *expr, struct acl_test *test)
 {
 	struct http_txn *txn = l7;
 	char *ptr;
@@ -5252,7 +5255,8 @@
 
 /* 3. Check on Status Code. We manipulate integers here. */
 static int
-acl_fetch_stcode(struct proxy *px, struct session *l4, void *l7, int dir, void *arg, struct acl_test *test)
+acl_fetch_stcode(struct proxy *px, struct session *l4, void *l7, int dir,
+                 struct acl_expr *expr, struct acl_test *test)
 {
 	struct http_txn *txn = l7;
 	char *ptr;
@@ -5268,7 +5272,8 @@
 
 /* 4. Check on URL/URI. A pointer to the URI is stored. */
 static int
-acl_fetch_url(struct proxy *px, struct session *l4, void *l7, int dir, void *arg, struct acl_test *test)
+acl_fetch_url(struct proxy *px, struct session *l4, void *l7, int dir,
+              struct acl_expr *expr, struct acl_test *test)
 {
 	struct http_txn *txn = l7;