webadmin,userportal: do not add default nic on edit vm

If the VM had no nics the edit VM added a default one and
tried to edit it. It was not correct - if the VM has no
nics than the edit should not add any.

Change-Id: I21724b30dc1ad6ccbbe40448ad77c47c22123c06
Bug-Url: https://bugzilla.redhat.com/995048
Signed-off-by: Tomas Jelinek <tjelinek@redhat.com>