Handle nested arrays

Handle nested arrays

We actually need mdadm(8) changes for this to work properly otherwise
the MD_* properties end up overwriting each other.

We also have to be careful since a single GUdevDevice instance can be
in two distinct UDisksLinuxMDRaidObject.

http://people.freedesktop.org/~david/gnome-disks-mdraid-20120920-1.png

Signed-off-by: David Zeuthen <zeuthen@gmail.com>