Revert "Remove 'ceph-deploy osd activate'"

This commit should not have been merged into stable/6.0 branch before 6.0 release.

Related-bug: #1374160

This reverts commit fb5837947c25ab76d03b8bb7f666e59719fa0165.

Change-Id: Ia60cc52320dcbc48fbe1b25d7b867f20f20b4347
Merge "Revert "Remove 'ceph-deploy osd activate'"" into stable/6.0