Fixes an issue with 'dd' bug from Illumos repo

The Illumos version of 'dd' never stops in case of count=0.
Thus 'truncate' should be used for creating a sparsed file.

Change-Id: I7a1840e2c43a27c648e5f65c2a87286311a34516
Merge "Fixes an issue with 'dd' bug from Illumos repo"