Add a method to extract information about an mdraid array
Add a method to extract information about an mdraid array

mdadm --detail can give useful information about the number of spare devices
and other things that mdadm --examine can not. According to the man page
--examine applies to devices which are components of an array, while --detail
applies to a whole array which is currently active.

Signed-off-by: mulhern <7b51bcf507bcd7afb72bf8663752c0ddbeb517f6@redhat.com>

dwlehman/blivet,vojtechtrefny/blivet,AdamWill/blivet,jkonecny12/blivet,vpodzime/blivet,dwlehman/blivet,AdamWill/blivet,rhinstaller/blivet,jkonecny12/blivet,rvykydal/blivet,rvykydal/blivet,vojtechtrefny/blivet,vpodzime/blivet,rhinstaller/blivet