Fix dumping role comments when using --no-role-passwords

Commit 9a83d56b38 added support for allowing pg_dumpall to dump
roles without including passwords, which accidentally made dumps
omit COMMENTs on roles.  This fixes it by using pg_authid to get
the comment.

Backpatch to all supported versions. Patch simultaneously written
independently by Álvaro and myself.

Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Author: Daniel Gustafsson <daniel@yesql.se>
Reported-by: Bartosz Chroł <bartosz.chrol@handen.pl>
Discussion: https://postgr.es/m/AS8P194MB1271CDA0ADCA7B75FCD8E767F7332@AS8P194MB1271.EURP194.PROD.OUTLOOK.COM
Discussion: https://postgr.es/m/CAEP4nAz9V4H41_4ESJd1Gf0v%3DdevkqO1%3Dpo91jUw-GJSx8Hxqg%40mail.gmail.com
Backpatch-through: v12

src/bin/pg_dump/pg_dumpall.c

@@ -736,28 +736,31 @@ dumpRoles(PGconn *conn)
 				i_is_current_user;
 	int			i;
 
-	/* note: rolconfig is dumped later */
+	/*
+	 * Notes: rolconfig is dumped later, and pg_authid must be used for
+	 * extracting rolcomment regardless of role_catalog.
+	 */
 	if (server_version >= 90600)
 		printfPQExpBuffer(buf,
 						  "SELECT oid, rolname, rolsuper, rolinherit, "
 						  "rolcreaterole, rolcreatedb, "
 						  "rolcanlogin, rolconnlimit, rolpassword, "
 						  "rolvaliduntil, rolreplication, rolbypassrls, "
-						  "pg_catalog.shobj_description(oid, '%s') as rolcomment, "
+						  "pg_catalog.shobj_description(oid, 'pg_authid') as rolcomment, "
 						  "rolname = current_user AS is_current_user "
 						  "FROM %s "
 						  "WHERE rolname !~ '^pg_' "
-						  "ORDER BY 2", role_catalog, role_catalog);
+						  "ORDER BY 2", role_catalog);
 	else if (server_version >= 90500)
 		printfPQExpBuffer(buf,
 						  "SELECT oid, rolname, rolsuper, rolinherit, "
 						  "rolcreaterole, rolcreatedb, "
 						  "rolcanlogin, rolconnlimit, rolpassword, "
 						  "rolvaliduntil, rolreplication, rolbypassrls, "
-						  "pg_catalog.shobj_description(oid, '%s') as rolcomment, "
+						  "pg_catalog.shobj_description(oid, 'pg_authid') as rolcomment, "
 						  "rolname = current_user AS is_current_user "
 						  "FROM %s "
-						  "ORDER BY 2", role_catalog, role_catalog);
+						  "ORDER BY 2", role_catalog);
 	else
 		printfPQExpBuffer(buf,
 						  "SELECT oid, rolname, rolsuper, rolinherit, "
@@ -765,10 +768,10 @@ dumpRoles(PGconn *conn)
 						  "rolcanlogin, rolconnlimit, rolpassword, "
 						  "rolvaliduntil, rolreplication, "
 						  "false as rolbypassrls, "
-						  "pg_catalog.shobj_description(oid, '%s') as rolcomment, "
+						  "pg_catalog.shobj_description(oid, 'pg_authid') as rolcomment, "
 						  "rolname = current_user AS is_current_user "
 						  "FROM %s "
-						  "ORDER BY 2", role_catalog, role_catalog);
+						  "ORDER BY 2", role_catalog);
 
 	res = executeQuery(conn, buf->data);