The function CRM_Import_DataSource_SQL::buildQuickForm() should be declared static.

The attached patch resolves the following PHP warning notice:
Strict warning: Non-static method CRM_Import_DataSource_SQL::buildQuickForm() should not be called statically, assuming $this from incompatible context in eval() (line 1 of /var/www/sites/all/modules/civicrm/CRM/Import/Form/DataSource.php(127) : eval()'d code).