Fix ac218aa to work on versions before 9.5.

Unfortunately ac218aa missed the fact that a reference to
'pg_catalog.regnamespace'::regclass wouldn't work before that type is
known. Fix that, by replacing the regtype usage with a join to
pg_type.

Reported-By: Tom Lane
Author: Andres Freund
Discussion: https://postgr.es/m/8863.1543297423@sss.pgh.pa.us
Backpatch: 9.5-, like ac218aa

Author: anarazel

src/bin/pg_upgrade/check.c

@@ -915,18 +915,23 @@ check_for_reg_data_type_usage(ClusterInfo *cluster)
 								"SELECT n.nspname, c.relname, a.attname "
 								"FROM	pg_catalog.pg_class c, "
 								"		pg_catalog.pg_namespace n, "
-								"		pg_catalog.pg_attribute a "
+								"		pg_catalog.pg_attribute a, "
+								"		pg_catalog.pg_type t "
 								"WHERE	c.oid = a.attrelid AND "
 								"		NOT a.attisdropped AND "
-								"		a.atttypid IN ( "
+								"       a.atttypid = t.oid AND "
+								"       t.typnamespace = "
+								"           (SELECT oid FROM pg_namespace "
+								"            WHERE nspname = 'pg_catalog') AND"
+								"		t.typname IN ( "
 		/* regclass.oid is preserved, so 'regclass' is OK */
-								"			'pg_catalog.regconfig'::pg_catalog.regtype, "
-								"			'pg_catalog.regdictionary'::pg_catalog.regtype, "
-								"			'pg_catalog.regnamespace'::pg_catalog.regtype, "
-								"			'pg_catalog.regoper'::pg_catalog.regtype, "
-								"			'pg_catalog.regoperator'::pg_catalog.regtype, "
-								"			'pg_catalog.regproc'::pg_catalog.regtype, "
-								"			'pg_catalog.regprocedure'::pg_catalog.regtype "
+								"           'regconfig', "
+								"           'regdictionary', "
+								"           'regnamespace', "
+								"           'regoper', "
+								"           'regoperator', "
+								"           'regproc', "
+								"           'regprocedure' "
 		/* regrole.oid is preserved, so 'regrole' is OK */
 		/* regtype.oid is preserved, so 'regtype' is OK */
 								"			) AND "