make search function use search_with_scope

[davidcoutadeur]

We could add a new argument with a default value to the search method:

function search($ldap_filter,$attributes, $attributes_map, $search_result_title, $search_result_sortby, $search_result_items, $search_scope = "sub")

The last argument won't be necessary as it has a default value, thus not requiring us to update all method signatures everywhere.