Use ListInstance typedef in more places

Change-Id: Ic41218a1e09f76d7455816163d9b3ca24b0b94ca
diff --git a/src/ast_path.hpp b/src/ast_path.hpp
index 2d809bc..9138946 100644
--- a/src/ast_path.hpp
+++ b/src/ast_path.hpp
@@ -65,7 +65,7 @@
 
 struct listElement_ {
     listElement_() {}
-    listElement_(const std::string& listName, const std::map<std::string, leaf_data_>& keys);
+    listElement_(const std::string& listName, const ListInstance& keys);
 
     bool operator==(const listElement_& b) const;