Remove iSCSI mounts from Kubelet

* Remove Kubelet `/etc/iscsi` and `iscsiadm` host mounts that
were added on bare-metal, since these no longer work on either
Fedora CoreOS or Flatcar Linux with newer `iscsiadm`
* These special mounts on bare-metal date back to #350 which
added them to provide a way to use iSCSI in Kubernetes v1.10
* Today, storage should be handled by external CSI providers
which handle different storage systems, which doesn't rely
on Kubelet storage utils

Close #907

bare-metal/flatcar-linux/kubernetes/cl/controller.yaml

@@ -88,8 +88,6 @@ systemd:
           -v /var/lib/kubelet:/var/lib/kubelet:rshared \
           -v /var/log:/var/log \
           -v /opt/cni/bin:/opt/cni/bin \
-          -v /etc/iscsi:/etc/iscsi \
-          -v /usr/sbin/iscsiadm:/usr/sbin/iscsiadm \
           $${KUBELET_IMAGE} \
           --anonymous-auth=false \
           --authentication-token-webhook \

bare-metal/flatcar-linux/kubernetes/cl/worker.yaml

@@ -63,8 +63,6 @@ systemd:
           -v /var/lib/kubelet:/var/lib/kubelet:rshared \
           -v /var/log:/var/log \
           -v /opt/cni/bin:/opt/cni/bin \
-          -v /etc/iscsi:/etc/iscsi \
-          -v /usr/sbin/iscsiadm:/usr/sbin/iscsiadm \
           $${KUBELET_IMAGE} \
           --anonymous-auth=false \
           --authentication-token-webhook \