Add requirement for kubeconfig for e2e repeat test

Signed-off-by: Kennelly, Martin <martin.kennelly@intel.com>

doc/testing-kind.md

@@ -13,6 +13,7 @@ Note: Test device will remain in KinD worker node until cluster is terminated.
 ### How to repeat test using existing KinD cluster
 Export test PCI device used to set up KinD cluster and export KinD worker network namespace path:
 ```
+$ export KUBECONFIG="${HOME}/.kube/config"
 $ export TEST_PCI_DEVICE=0000:02:00.0
 $ export TEST_NETNS_PATH=$(docker inspect "$(docker ps --filter 'name=kind-worker' -q)" --format "{{ .NetworkSettings.SandboxKey }}")
 $ sudo make test-e2e-k8s