build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/github.com/mistifyio/go-zfs/README.md

@@ -0,0 +1,54 @@
+# Go Wrapper for ZFS #
+
+Simple wrappers for ZFS command line tools.
+
+[![GoDoc](https://godoc.org/github.com/mistifyio/go-zfs?status.svg)](https://godoc.org/github.com/mistifyio/go-zfs)
+
+## Requirements ##
+
+You need a working ZFS setup.  To use on Ubuntu 14.04, setup ZFS:
+
+    sudo apt-get install python-software-properties
+    sudo apt-add-repository ppa:zfs-native/stable
+    sudo apt-get update
+    sudo apt-get install ubuntu-zfs libzfs-dev
+
+Developed using Go 1.3, but currently there isn't anything 1.3 specific. Don't use Ubuntu packages for Go, use http://golang.org/doc/install
+
+Generally you need root privileges to use anything zfs related.
+
+## Status ##
+
+This has been only been tested on Ubuntu 14.04
+
+In the future, we hope to work directly with libzfs.
+
+# Hacking #
+
+The tests have decent examples for most functions.
+
+```go
+//assuming a zpool named test
+//error handling omitted
+
+
+f, err := zfs.CreateFilesystem("test/snapshot-test", nil)
+ok(t, err)
+
+s, err := f.Snapshot("test", nil)
+ok(t, err)
+
+// snapshot is named "test/snapshot-test@test"
+
+c, err := s.Clone("test/clone-test", nil)
+
+err := c.Destroy()
+err := s.Destroy()
+err := f.Destroy()
+
+```
+
+# Contributing #
+
+See the [contributing guidelines](./CONTRIBUTING.md)
+