fix vendor dep casing

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

vendor/github.com/Sirupsen/logrus/terminal_check_notappengine.go

@@ -0,0 +1,19 @@
+// +build !appengine,!gopherjs
+
+package logrus
+
+import (
+	"io"
+	"os"
+
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+func checkIfTerminal(w io.Writer) bool {
+	switch v := w.(type) {
+	case *os.File:
+		return terminal.IsTerminal(int(v.Fd()))
+	default:
+		return false
+	}
+}

vendor/github.com/sirupsen/logrus/terminal_check_appengine.go

@@ -1,11 +0,0 @@
-// +build appengine gopherjs
-
-package logrus
-
-import (
-	"io"
-)
-
-func checkIfTerminal(w io.Writer) bool {
-	return true
-}

vendor/vendor.json

@@ -233,6 +233,12 @@
 			"revision": "c2e73f942591b0f033a3c6df00f44badb2347c38",
 			"revisionTime": "2018-01-10T05:50:12Z"
 		},
+		{
+			"checksumSHA1": "2PBDgrQHH6ZDxBWs6Z4imBzdEjk=",
+			"path": "github.com/Sirupsen/logrus",
+			"revision": "90150a8ed11b6ce285e77e8af2b0109559ce4777",
+			"revisionTime": "2018-03-15T01:07:03Z"
+		},
 		{
 			"checksumSHA1": "HttiPj314X1a0i2Jen1p6lRH/vE=",
 			"path": "github.com/aliyun/aliyun-oss-go-sdk/oss",
@@ -1195,12 +1201,6 @@
 			"revision": "51d0290d9434dc6139dd89001236cfd989521a79",
 			"revisionTime": "2018-03-05T22:44:21Z"
 		},
-		{
-			"checksumSHA1": "ByFN6xh/YGP/D3DM9c8p0D9D1XM=",
-			"path": "github.com/sirupsen/logrus",
-			"revision": "90150a8ed11b6ce285e77e8af2b0109559ce4777",
-			"revisionTime": "2018-03-15T01:07:03Z"
-		},
 		{
 			"checksumSHA1": "iydUphwYqZRq3WhstEdGsbvBAKs=",
 			"comment": "v1.1.4-4-g976c720",