osd: OSD device smart data include additional nvme data

osd: OSD device smart data include additional nvme data

Add nvme addition data into the deveh health data. That use nvme tool
and command syntax "nvme <vendor> smart-log-add <dev> -json". The nvme
json output append in the dev smart "nvme_smart_health_information_add_log".

- made run_smartctl static/private
- changed get_metrics to take a const string, not c str

Signed-off-by: Rick Chen <rick.chen@prophetstor.com>
Signed-off-by: Sage Weil <sage@redhat.com>