Fixed test - segmented upload of file

The manifest file should be empty. Previously, the data were saved into the
manifest file too, which could cause a false positive.
See http://docs.openstack.org/developer/swift/overview_large_objects.html

Made each segment different, not just data*10.

Change-Id: I6f5a10f2836d6c5d881486d29fc5714213ea4dc5
Merge "Fixed test - segmented upload of file"