Add what is needed for delete commands

Author: JoshInnis

regress/sql/vertex_am.sql

@@ -28,3 +28,12 @@ VALUES ('1'::postgraph.graphid, postgraph.gtype_build_map('id', 1));
 
 SELECT * FROM vertex_am_tst;
 
+DELETE FROM vertex_am_tst;
+
+INSERT INTO vertex_am_tst (id, props)
+VALUES ('1'::postgraph.graphid, postgraph.gtype_build_map('id', 1));
+
+
+SELECT * FROM vertex_am_tst;
+
+