fix pyZeroconf bug where getServiceInfo returns None.
This allows the discovery window to work with targets using Avahi to advertise their services.
(patch obtained from <http://sourceforge.net/tracker/?func=detail&aid=1600775&group_id=100909&atid=628622>)
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Interface xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.w3.org/2001/XMLSchema" xsi:schemaLocation="def_xsd.xsd" id="1" name="Interface">
<Button toggle="true" unselected_id="fill_off" selected_id="fill_on" id="2" name="fill" background_id="fill_bck"/>
<Button toggle="true" unselected_id="empty_off" selected_id="empty_on" id="3" name="empty" background_id="Empty_bck"/>
<Transform moving_id="gague_mobile" id="4" name="gauge" enable="false" background_id="gauge_bck"/>
</Interface>