Modify charm-ceph-mon to make it an python35 only for gate
Modify charm-ceph-mon to make it an python35 only for gate

AS charm-ceph-mon is now a py3 project, the charm needs to have a py3x
gate.

Depends-On: Iaf66c8a41cf5f14c4b665e9bd6c3cf39d82c29b2
Change-Id: Ie9e83598b29f64527ad2b947955ca430e496ab16

openstack-infra/project-config,openstack-infra/project-config