Implement the ceph osd destroy feature in ceph-deploy.

    1. handle osd already out
    2. handle osd did not blong any hostname
    3. handle osd is not in acting set

Usage: ceph-deploy osd destroy <hostname> --osd-id <osd-id>

I think it may be helpful for someone new to ceph who want to destroy osd.
If you have any questions, feel free to let me know.

Thanks!!

you could just raise an exception (e.g. `NotImplementedError`) *or* require it as part of the command.