LVM aligns devices data area to io hints, reported for
block devices. Optimal io size can be big for some devices
(16M, as reported in bug). So nailgun's volume manager
should take it into account while doing partitioning.
So nailgun-agent should send this information to nailgun.
Change-Id: Idd9b778f7f21d4fe9d3fd029038664de41f93447
Partial-Bug: #1546049