When i40e driver performs 'vf <n> trust on' it actually resets the device.
Intel recommends to check if the command actually finished by running
'ip link show' to avoid race-condition with too early start of
openvswitch-dpdk which will use its own dpdk-based driver for VF and which
will also try to reset the VF. Double reset of VF sometimes causes
very strange behavior including completely non-functional VF interface..
Change-Id: I28c162a63f89b3cdfe857e00651572bbbaa36748
552cab2ff1