Make sure the SQL functions are not quoted (Bug #1406372)

Change-Id: I8ac41fc9915e5ceb7be4b452164d5749b14470a0
Signed-off-by: Yuliya Bozhko <yuliya.bozhko@totaralms.com>

htdocs/lib/dml.php

@@ -52,7 +52,7 @@ function db_quote_identifier($identifier) {
     $identifier = trim($identifier);
     if (strpos($identifier, '"') !== false
         || $identifier === '*'
-        || preg_match('/count\(/i', $identifier)) {
+        || preg_match('/\(/i', $identifier)) {
         return $identifier;
     }
     return '"' . $identifier . '"';