Removing default for volume-plugins mountpoint (#2618)

All checks test if this is defined meaning there is no way to undefine it.

roles/kubernetes/node/templates/kubelet-container.j2

@@ -24,6 +24,11 @@
   -v /var/lib/kubelet:/var/lib/kubelet:shared \
   -v /var/lib/cni:/var/lib/cni:shared \
   -v /var/run:/var/run:rw \
+  {# we can run into issues with double mounting /var/lib/kubelet #}
+  {# surely there's a better way to do this #}
+  {% if '/var/lib/kubelet' not in kubelet_flexvolumes_plugins_dir %}
+  -v {{ kubelet_flexvolumes_plugins_dir }}:{{ kubelet_flexvolumes_plugins_dir }}:rw \
+  {% endif -%}
   -v {{kube_config_dir}}:{{kube_config_dir}}:ro \
   -v /etc/os-release:/etc/os-release:ro \
   {{ hyperkube_image_repo }}:{{ hyperkube_image_tag}} \