Database.php: allow all SQL commands.

extension/Source/core/database/Database.php

@@ -448,7 +448,11 @@ class Database {
                 break;
 
             default:
-                throw new DbException('Unknown command: "' . $command . '"' . $specificMessage, ERROR_DB_UNKNOWN_COMMAND);
+                // Unknown command: treat it as a control command
+                $queryType = QUERY_TYPE_CONTROL;
+                $stat[DB_AFFECTED_ROWS] = 0;
+                $count = $stat[DB_AFFECTED_ROWS];
+                $msg = '';
                 break;
         }