Veth devices are shown as NICs + test

Veth LinkType was not listed in tuple, therefore veths were
evaluated as NICs.

New test adds dummies and veths with _fakeNics prefix and with
non _fakeNics prefix and then verify if fake nics are shown in
netinfo.nics() and the others are not.

Bug-Url: https://bugzilla.redhat.com/1125177
Change-Id: Ide618510b46eee28d939c32e8188bbd38349d660
Signed-off-by: Petr Horáček <phoracek@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/31166
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>