retrive ovf disk interface and import to kvm box

Signed-off-by: Hiroshi Miura <miurahr@linux.com>
Merge branch 'respect_ovf_disk_interface' of git://github.com/miurahr/vagrant-mutate into miurahr-respect_ovf_disk_interface
Handle errors is disk interface cannot be determined
Fix namespace for DetermineImageSizeFailed
Handle remaining potential errors when reading ovf