Update curl.php

Fix: Strict Standards: Declaration of GC_Walker_PageDropdown::start_el() should be compatible with Walker::start_el(&$output, $object, $depth = 0, $args = Array, $current_object_id = 0)

Passing 'default' as base_name value. By passing `default` code will be compatible with l10n too.
Merge pull request #1 from thilanga/patch-1

Update curl.php