https://bugs.launchpad.net/fuel/+bug/1634691 shows that partition
preservation feature works on magic and shouldn't save partition
in current implementation (it relates on an another bug).
Change-Id: I2ea5f1b9f1db07a40f1f48346d6836ef96a07da9
Partial-bug:1656040
(cherry picked from commit a4804569eb)