Add sudo command for non-root account to mount osd

Generally we specify the user is root when deploying ceph, it is no
problem. But if we have the need to use a non-root account, the deployment
will fail because the non-root account can't use the mount command.
I think it is necessary to add sudo for non-root account, when we can't use
the root account to deploy ceph because of security needs, we can use
non-root account to deploy ceph.

Change-Id: Iea1f30bcf8edbe15dc65909bbae780b55a669067
Closes-Bug: #1668823

ansible/roles/ceph/tasks/start_osds.yml

@@ -19,6 +19,8 @@
     name: "/var/lib/ceph/osd/{{ item['fs_uuid'] }}"
     opts: "{{ ceph_osd_mount_options }}"
   with_items: "{{ osds }}"
+  become: true
+  become_method: sudo
 
 - name: Gathering OSD IDs
   command: "cat /var/lib/ceph/osd/{{ item['fs_uuid'] }}/whoami"