Changed APT proxy url to test (refs #28781).

tests/test_apt_proxy.py

@@ -35,7 +35,7 @@ conf_servers = (
 for s in conf_servers:
     v = conf.get(s)
     try:
-        url = 'https://%s/old-releases.ubuntu.com/ubuntu/dists/lucid/Release.gpg' % v
+        url = 'https://%s/panel.ubicast.eu/old-releases.ubuntu.com/ubuntu/dists/lucid/Release.gpg' % v
         print('Checking url certificate %s' % url)
         d = requests.get(url, verify=False).text
         if 'BEGIN PGP SIGNATURE' not in d: