engine: RemoveNetworksByLabelParametersBuilder accepts any vlan device name

Changes done in this patch-
1. The builder uses iface.getBaseInterface() and iface.getVlanId() instead
of determining this values from the vlan device name (since its format is
no longer- baseIface.vlanId).
2. The builder uses the new methods indroduced in NetworkUtils instead of
the old ones (that should be removed in a following patch).

Change-Id: If22225ae3d971aa6072b161df0965dd663deff1e
Bug-Url: https://bugzilla.redhat.com/1091863
Bug-Url: https://bugzilla.redhat.com/999975
Signed-off-by: Alona Kaplan <alkaplan@redhat.com>