Bring back BINARY for some columns after switch to utf8mb4 charset (#7277)

SQL/mysql/2020020101.sql

@@ -12,3 +12,10 @@ ALTER TABLE `dictionary` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicod
 ALTER TABLE `searches` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
 ALTER TABLE `filestore` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
 ALTER TABLE `system` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+
+ALTER TABLE `users` ALTER `username` varchar(128) BINARY NOT NULL;
+ALTER TABLE `cache` ALTER `cache_key` varchar(128) BINARY NOT NULL;
+ALTER TABLE `cache_shared` ALTER `cache_key` varchar(255) BINARY NOT NULL;
+ALTER TABLE `cache_index` ALTER `mailbox` varchar(255) BINARY NOT NULL;
+ALTER TABLE `cache_thread` ALTER `mailbox` varchar(255) BINARY NOT NULL;
+ALTER TABLE `cache_messages` ALTER `mailbox` varchar(255) BINARY NOT NULL;