tour: use simpler URL for German translation

Change-Id: I2f16fbfeabeebe5e6dee95dc40368f29495c5844
Reviewed-on: https://go-review.googlesource.com/7129
Reviewed-by: Minux Ma <minux@golang.org>
diff --git a/content/welcome.article b/content/welcome.article
index bd7abfa..9ce7d12 100644
--- a/content/welcome.article
+++ b/content/welcome.article
@@ -49,7 +49,7 @@
 
 - [[http://go-tour-br.appspot.com/][Brazilian Portuguese — Português do Brasil]]
 - [[http://go-tour-ca.appspot.com/][Catalan — Català]]
-- [[http://go-tour-de1.appspot.com/][German — Deutsch]]
+- [[http://go-tour-de.appspot.com/][German — Deutsch]]
 - [[http://go-tour-es.appspot.com/][Spanish — Español]]
 - [[http://go-tour-fr.appspot.com/][French — Français]]
 - [[http://go-tour-ita.appspot.com/][Italian — Italiano]]