Fix the vagrant deployment

Fix the vagrant deployment

Add a fetch/ceph_cluster_uuid.conf file so we keep the same UUID from
the Vagrantfile and from the ceph-common run.
Prior to that change the Vagrantfile was setting
4a158d27-f750-41d5-9e7f-26ce4c9d2d45 but while playing the ceph-common
role we check if fetch/ceph_cluster_uuid.conf exists, if not we generate
an UUID. Here we ended up with 2 UUIDs...

IMPORTANT NOTE FOR NON-VAGRANT DEPLOYMENT. IF YOU WANT TO USE YOUR OWN
UUID PLEASE REMOVE THAT FILE BEFORE RUNNING THE PLAYBOOK.

Signed-off-by: Sébastien Han <sebastien.han@enovance.com>