system tests: use repository mirrors on S3 for reproducibility

no direct internet download from apt repositories,
which over time will change or cease to exist.

also migrate to gpg2 on newer ubuntu.

system/t12_api/tasks.py

@@ -10,8 +10,9 @@ class TaskAPITestParallelTasks(APITest):
     def _create_mirror(self, dist):
         mirror_name = self.random_name()
         mirror_desc = {'Name': mirror_name,
-                       'ArchiveURL': 'https://packagecloud.io/varnishcache/varnish30/debian/',
+                       'ArchiveURL': 'http://repo.aptly.info/system-tests/packagecloud.io/varnishcache/varnish30/debian/',
                        'Distribution': dist,
+                       'Architectures': ["amd64", "i386"],
                        'Components': ['main']}
         mirror_desc['IgnoreSignatures'] = True
         resp = self.post("/api/mirrors", json=mirror_desc)
@@ -76,7 +77,7 @@ class TaskAPITestParallelTasks(APITest):
     def check(self):
         publish_task_ids = []
         mirror_task_list = []
-        for mirror_dist in ['squeeze', 'jessie']:
+        for mirror_dist in ['squeeze', 'wheezy']:
             mirror_task_id, mirror_name = self._create_mirror(mirror_dist)
             mirror_task_list.append((mirror_task_id, mirror_name))
         repo_task_id, repo_name = self._create_repo()