e2e: retry when a "transport is closing" error is hit
e2e: retry when a "transport is closing" error is hit

There have been occasional CI job failures due to "transport is closing"
errors. Adding this error to the isRetryableAPIError() function should
make sure to retry the request until the connection is restored.

Fixes: #2613
Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi