Remove redundant repository mirantis_openstack_proposed

Currently in respository list mos9.0-proposed from
http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/ is used and in fact
it have same packages as mos9.0-updates.
There are mos9.0-updates is enough for right deployment

https://github.com/Mirantis/mk-lab-salt-model/pull/185
diff --git a/linux/system/repo/mos9.yml b/linux/system/repo/mos9.yml
index 70cb2d2..9bc7c8c 100644
--- a/linux/system/repo/mos9.yml
+++ b/linux/system/repo/mos9.yml
@@ -10,10 +10,6 @@
           source: "deb http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/ mos9.0-hotfix main restricted"
           architectures: amd64
           key_url: "http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/archive-mos9.0.key"
-        mirantis_openstack_proposed:
-          source: "deb http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/ mos9.0-proposed main restricted"
-          architectures: amd64
-          key_url: "http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/archive-mos9.0.key"
         mirantis_openstack_security:
           source: "deb http://mirror.fuel-infra.org/mos-repos/ubuntu/9.0/ mos9.0-security main restricted"
           architectures: amd64