Remove unused 'panels' variable

Besides being unused, it overrides panels() function. While it isn't
used in this script, it isn't clear (to me) what scope does it have, and
it might be relevant to other scripts.

11-qubes.js

@@ -1,5 +1,4 @@
 /* replace the default kickoff with Qubes menu */
-var panels = panels()
 for (var i in panelIds) {
 	var panel = panelById(panelIds[i])
 	var widgetIds = panel.widgetIds