db-oar: fix api.insert_user_metrics function definition

kwollect/db/kwollect_setup_db_oar.py

@@ -119,7 +119,7 @@ END;
 $$ LANGUAGE 'plpgsql';
 
 
-DROP FUNCTION api.insert_user_metrics;
+DROP FUNCTION IF EXISTS api.insert_user_metrics;
 CREATE OR REPLACE FUNCTION api.insert_user_metrics(JSON)
 RETURNS INT AS $$