core: list iptables sharing rules in the right order

The rules were added to the list using g_slist_append() and then
applied one at time using "iptables --insert" which puts them at the
beginning of the chain, reversing the initial order.

Instead, list them in the desired order and use g_slist_prepend() to
achieve the same result. This has no functional changes.

src/nm-activation-request.c

@@ -346,7 +346,7 @@ nm_act_request_add_share_rule (NMActRequest *req,
 	rule = g_malloc0 (sizeof (ShareRule));
 	rule->table = g_strdup (table);
 	rule->rule = g_strdup (table_rule);
-	priv->share_rules = g_slist_append (priv->share_rules, rule);
+	priv->share_rules = g_slist_prepend (priv->share_rules, rule);
 }
 
 /********************************************************************/