Try to wait after stopping an MD array
Try to wait after stopping an MD array

Sometimes after running 'mdadm --stop' it takes some time before
the device in /dev disappears. udev settle should fix this.

Resolves: rhbz#1563631

vojtechtrefny/blivet,rvykydal/blivet,vojtechtrefny/blivet,jkonecny12/blivet,rvykydal/blivet,jkonecny12/blivet