[Web] Fix init_db, init json when attributes are null

data/web/inc/init_db.inc.php

@@ -964,7 +964,7 @@ DELIMITER ;';
     $stmt = $pdo->query("REPLACE INTO `versions` (`application`, `version`) VALUES ('db_schema', '" . $db_version . "');"); 
 
     // Migrate attributes
-    $stmt = $pdo->query("UPDATE `mailbox` SET `attributes` = '{}' WHERE `attributes` = '' OR NULL;");
+    $stmt = $pdo->query("UPDATE `mailbox` SET `attributes` = '{}' WHERE `attributes` = '' OR `attributes` IS NULL;");
     $stmt = $pdo->query("UPDATE `mailbox` SET `attributes` =  JSON_SET(`attributes`, '$.force_pw_update', \"0\") WHERE JSON_EXTRACT(`attributes`, '$.force_pw_update') IS NULL;");
     $stmt = $pdo->query("UPDATE `mailbox` SET `attributes` =  JSON_SET(`attributes`, '$.sogo_access', \"1\") WHERE JSON_EXTRACT(`attributes`, '$.sogo_access') IS NULL;");
     $stmt = $pdo->query("UPDATE `mailbox` SET `attributes` =  JSON_SET(`attributes`, '$.mailbox_format', \"maildir:\") WHERE JSON_EXTRACT(`attributes`, '$.mailbox_format') IS NULL;");