[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/github.com/sirupsen/logrus/appveyor.yml b/vendor/github.com/sirupsen/logrus/appveyor.yml
new file mode 100644
index 0000000..96c2ce1
--- /dev/null
+++ b/vendor/github.com/sirupsen/logrus/appveyor.yml
@@ -0,0 +1,14 @@
+version: "{build}"

+platform: x64

+clone_folder: c:\gopath\src\github.com\sirupsen\logrus

+environment:  

+  GOPATH: c:\gopath

+branches:  

+  only:

+    - master

+install:  

+  - set PATH=%GOPATH%\bin;c:\go\bin;%PATH%

+  - go version

+build_script:  

+  - go get -t

+  - go test