Suppress "variable may be used uninitialized" warning.

Also re-pgindent, just because I'm a neatnik.

src/backend/commands/policy.c

@@ -656,7 +656,7 @@ AlterPolicy(AlterPolicyStmt *stmt)
 	Oid			policy_id;
 	Relation	target_table;
 	Oid			table_id;
-	Datum	   *role_oids;
+	Datum	   *role_oids = NULL;
 	int			nitems = 0;
 	ArrayType  *role_ids = NULL;
 	List	   *qual_parse_rtable = NIL;