If the guest network adapter is not configured with DeviceNaming
enabled on the host, then the query for friendly name will return
success but with a zero length name. Which then leads to a garbage value
(stack contents) for ifalias.
Fix is simple, just don't set name if host doesn't return it.
Fixes: 0fe554a46a0f ("hv_netvsc: propogate Hyper-V friendly name into interface alias") Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>