js: Fix up for Clutter.Color changes

Spotted by darkxst on IRC.

https://bugzilla.gnome.org/show_bug.cgi?id=683073

js/ui/lookingGlass.js

@@ -38,7 +38,6 @@ var commandHeader = 'const Clutter = imports.gi.Clutter; ' +
                     /* Utility functions...we should probably be able to use these
                      * in the shell core code too. */
                     'const stage = global.stage; ' +
-                    'const color = function(pixel) { let c= new Clutter.Color(); c.from_pixel(pixel); return c; }; ' +
                     /* Special lookingGlass functions */
                     'const it = Main.lookingGlass.getIt(); ' +
                     'const r = Lang.bind(Main.lookingGlass, Main.lookingGlass.getResult); ';