proper pattern (amending da5cc332ded3);

--- a/src/Pure/Tools/build_process.scala	Thu Jun 15 14:28:17 2023 +0200
+++ b/src/Pure/Tools/build_process.scala	Thu Jun 15 14:44:12 2023 +0200
@@ -864,6 +864,7 @@
       case db_progress: Database_Progress =>
         db_progress.exit()
         db_progress.db.close()
+      case _ =>
     }
   }