This reread_partitions method was a desperate attempt
to work around udev related "device is busy" error.
The correct way to deal with that stuff is to use
udevadm --settle which is to block thread until udev is
ready to handle events.
Closes-Bug: 1410471
Change-Id: Idb0dccb35aab10d02c5ad942fd30d52a461e1a0e