webadmin: Accept vlan devices identified by any name

Vlan device name is no longer in the format baseInterface.vlanId.
Vlan id and base interface name can be detemined by-
vlanDevice.getVlanId(), vlanDevice.getBaseInterface().

Change-Id: Ic871fe32377e1b972315aa9c21d9e5cfabd03a03
Bug-Url: https://bugzilla.redhat.com/1091863
Bug-Url: https://bugzilla.redhat.com/999975
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>