network: use iproute instead of vconfig

oVirt Node uses vconfig tool only to delete vlans.
This tool is deprecated in favor of "ip link" command.

Change-Id: Ib73e74c3c90ce28ff88cc1a80dc41f79121932b1
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1127682
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>