added sftp client implementation

vendor/github.com/pkg/sftp/request_windows.go

@@ -0,0 +1,44 @@
+package sftp
+
+import (
+	"path"
+	"path/filepath"
+	"syscall"
+)
+
+func fakeFileInfoSys() interface{} {
+	return syscall.Win32FileAttributeData{}
+}
+
+func testOsSys(sys interface{}) error {
+	return nil
+}
+
+func toLocalPath(p string) string {
+	lp := filepath.FromSlash(p)
+
+	if path.IsAbs(p) {
+		tmp := lp
+		for len(tmp) > 0 && tmp[0] == '\\' {
+			tmp = tmp[1:]
+		}
+
+		if filepath.IsAbs(tmp) {
+			// If the FromSlash without any starting slashes is absolute,
+			// then we have a filepath encoded with a prefix '/'.
+			// e.g. "/C:/Windows" to "C:\\Windows"
+			return tmp
+		}
+
+		tmp += "\\"
+
+		if filepath.IsAbs(tmp) {
+			// If the FromSlash without any starting slashes but with extra end slash is absolute,
+			// then we have a filepath encoded with a prefix '/' and a dropped '/' at the end.
+			// e.g. "/C:" to "C:\\"
+			return tmp
+		}
+	}
+
+	return lp
+}