Changes to the OS support, multi-data center, and hypervisor questions.

Signed-off-by: Neil Levine <neil.levine@inktank.com>
Grammar typo

Signed-off-by: Neil Levine <neil.levine@inktank.com>
Minor wording change.

Signed-off-by: Neil Levine <neil.levine@inktank.com>
Merge git://github.com/ceph/ceph