Retries are attempted if VF configuration fails
Retries are attempted if VF configuration fails

When DPDK drivers are bound to a VF, it takes a while for the
succesfull configuration of the VFs via 'ip link' commands.
In order to facilitate the VF configuration, retries are made.

Change-Id: Ia6805a422c72c91e4a506c75498f841ef9cb6342

openstack/os-net-config