vt7.4 - global search fields are not easily modifiable per module

When searching using global search bar (top of screen) all search results are determined using Vtiger_Record_Model::getSearchResult() - even if various modules have overridden this method in module specific Record model definition eg. /modules/Leads/models/Record.php

changing how /modules/Vtiger/views/ListAjax.php searchAll() function calls getSearchResult() can allow it to use the overridden method instead of the base one. i.e. calling Leads_Record_Model::getSearchResult() instead of Vtiger_Record_Model::getSearchResult() would make use of the overridden function.