[VOL-2193] Create mocks for Kafka Client and Etcd

This commit consists of:
1) A kafka client mock that implements the kafka client interface
under voltha-lib-go/pkg/kafka/client.go
2) An embedded Etcd server that runs in-process and represents an
Etcd server.

Change-Id: I52a36132568e08c596bb4136918bebcb654a3b99
diff --git a/vendor/golang.org/x/sys/windows/types_windows_arm.go b/vendor/golang.org/x/sys/windows/types_windows_arm.go
new file mode 100644
index 0000000..74571e3
--- /dev/null
+++ b/vendor/golang.org/x/sys/windows/types_windows_arm.go
@@ -0,0 +1,22 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package windows
+
+type WSAData struct {
+	Version      uint16
+	HighVersion  uint16
+	Description  [WSADESCRIPTION_LEN + 1]byte
+	SystemStatus [WSASYS_STATUS_LEN + 1]byte
+	MaxSockets   uint16
+	MaxUdpDg     uint16
+	VendorInfo   *byte
+}
+
+type Servent struct {
+	Name    *byte
+	Aliases **byte
+	Port    uint16
+	Proto   *byte
+}