vdsm: drop uploadVolume usage

uploadVolume has been removed from VDSM API.
The new API downloadImage doesn't support local files.
Importing the OVA / OVF image using qemu-img for ensuring
it's in RAW format.

Bug-Url: https://bugzilla.redhat.com/1034777
Change-Id: I50700f1e64c396e72c4ed3a53196e6b704cf3d96
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>