- Added missing OpenACS 5.9.1 upgrade scripts

sql/postgresql/upgrade/upgrade-5.9.1b3-5.9.1b4.sql

+
+-- Before we were forgetting to delete acs_object. Now we exploit
+-- cascade constraint on service contract table. TODO: put cascade
+-- constraints on other tables referencing service contracts (like
+-- authorities table)
+
+CREATE OR REPLACE FUNCTION acs_sc_impl__delete(
+   p_impl_contract_name varchar,
+   p_impl_name varchar
+) RETURNS integer AS $$
+DECLARE
+   v_impl_id integer;
+BEGIN
+
+    v_impl_id := acs_sc_impl__get_id(p_impl_contract_name,p_impl_name);
+
+    perform acs_object__delete(v_impl_id);
+
+    return 0;
+
+END;
+$$ LANGUAGE plpgsql;