Fix warning: Parameter 6 to emvideo_slideshare_video() expected to be a reference, value given

This warning appears when using slideshare 6.x-1.x-dev and emfield 6.x-1.26 with PHP 5.3:


warning: Parameter 6 to emvideo_slideshare_video() expected to be a reference, value given in .../emfield.module on line 622.


This is related both to PHP 5.3 call_user_func_array() and to http://drupal.org/node/597664 and is fixed with the attached trivial patch (in this specific case, it's necessary to remove references from function signatures too).