Switch maas streams to mirror.mirantis.com

Change-Id: I10a5b4b769f4f2951aab7fc079edb26fff49913c
diff --git a/init.yml b/init.yml
index 8480126..ca2468e 100644
--- a/init.yml
+++ b/init.yml
@@ -533,7 +533,7 @@
         release:
           xenial:
             keyring: /usr/share/keyrings/ubuntu-cloudimage-keyring.gpg
-            upstream: http://images.maas.io/ephemeral-v3/daily/
+            upstream: http://mirror.mirantis.com/${_param:apt_mk_version}/maas-ephemeral-v3/
             local_dir: /var/www/html/maas/images/ephemeral-v3/daily
             arch: amd64
-            count: 1
\ No newline at end of file
+            count: 1