contrib: move x2goclient from pre-installed to offline repo

contrib/rootfs/offline_repo.json

@@ -86,6 +86,11 @@
             "pkgdescription": "LAPACK Dokumentation (s. oben)",
             "tagged": false
         },
+        {
+            "pkgname": "x2goclient",
+            "pkgdescription": "Remote Desktop Client (z.B. für den RBI-Pool",
+            "tagged": true
+        },
         {
             "pkgname": "linux-image-4.3.0-040300-rc2-generic_4.3.0",
             "pkgdescription": "Vanilla Linux Kernel",

contrib/rootfs/pre_installed_packages

@@ -8,7 +8,6 @@ kde-config-gtk-style
 libav-tools
 hunspell
 vlc
-x2goclient
 p7zip-full
 unrar-free
 kile