When eth_virtio_dev_init() is cleaning up, it does not correctly set
the mac_addrs variable to NULL, which will lead to a double free.
Found during unit-test fixes.
Fixes: 43d18765c0 ("net/virtio: fix memory leak on failure")
Cc: stable@dpdk.org
Reported-by: Michael Santana <msantana@redhat.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>
Reviewed-by: Tiwei Bie <tiwei.bie@intel.com>