Require UserCountry functions.php file in UserCountryMap so UI tests won't...

Require UserCountry functions.php file in UserCountryMap so UI tests won't fail (a request from the widgetized dashboard to the UserCountryMap failed because a function in this file was not available).

plugins/UserCountryMap/Controller.php

@@ -18,6 +18,8 @@ use Piwik\Site;
 use Piwik\Translation\Translator;
 use Piwik\View;
 
+require_once PIWIK_INCLUDE_PATH . '/plugins/UserCountry/functions.php';
+
 /**
  *
  */