Use HTTPS for piwik when loading via HTTPS

src/UI/Shared/NzbDroneController.js

@@ -24,7 +24,7 @@ module.exports = Marionette.AppRouter.extend({
 
         if (window.NzbDrone.Analytics && window.Piwik) {
             try {
-                var piwik = window.Piwik.getTracker('http://piwik.nzbdrone.com/piwik.php', 1);
+                var piwik = window.Piwik.getTracker(window.location.protocol + '//piwik.nzbdrone.com/piwik.php', 1);
                 piwik.setReferrerUrl('');
                 piwik.setCustomUrl('http://local' + window.location.pathname);
                 piwik.setCustomVariable(1, 'version', window.NzbDrone.Version, 'page');