add GDrive provider support (#118)

* GDrive provider support
* More reliable basedir ownership
* Fix mimetype

vendor/google.golang.org/api/gensupport/header_test.go

@@ -0,0 +1,28 @@
+// Copyright 2017 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 gensupport
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestGoogleClientHeader(t *testing.T) {
+	const genVersion = "20170101"
+	gv := strings.Replace(runtime.Version(), " ", "_", -1)
+	got := GoogleClientHeader(genVersion, "gccl/xyz")
+	want := fmt.Sprintf("gl-go/%s gccl/xyz gdcl/%s", gv, genVersion)
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+
+	got = GoogleClientHeader(genVersion, "")
+	want = fmt.Sprintf("gl-go/%s gdcl/%s", gv, genVersion)
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}