Patch to fix PHP notice message

Hi,

Not really a bug, but since I tend to also include notices in PHP's error reportings (for developing purposes), and this module generates one, I included a patch which will correct this. The notice message I got is below :

notice: Undefined variable: output in /var/www/html/sites/all/modules/local_menu/local_menu.module on line 117.
notice: Undefined variable: output in /var/www/html/sites/all/modules/local_menu/local_menu.module on line 117.

Hopefully this helps and thanks for the useful module!