tabs_update_1 causes error when running update.php

tabs_update_1 in tabs.install doesn't return anything and it causes error (but does nothing wrong further).

    * warning: array_merge() [function.array-merge]: Argument #2 is not an array in /var/www/htdocs/update.php on line 174.
    * warning: Invalid argument supplied for foreach() in /var/www/htdocs/update.php on line 338.

here is a patch to suppress this error message.