Remove pkg/storage (#727)

It's not used, remove it.

middleware/pkg/storage/fs.go

-// Package storage abstracts away where middleware can store assests (zones, keys, etc).
-package storage
-
-import (
-	"net/http"
-	"os"
-	"path"
-	"path/filepath"
-	"runtime"
-)
-
-// dir wraps an http.Dir that restrict file access to a specific directory tree, see http.Dir's documentation
-// for methods for accessing files.
-type dir http.Dir
-
-// CoreDir is the directory where middleware can store assets, like zone files after a zone transfer
-// or public and private keys or anything else a middleware might need. The convention is to place
-// assets in a subdirectory named after the zone prefixed with "D", to prevent the root zone become a hidden directory.
-//
-// Dexample.org/Kexample.org<something>.key
-//
-// Note that subzone(s) under example.org are places in the own directory under CoreDir:
-//
-// Dexample.org/...
-// Db.example.org/...
-//
-// CoreDir will default to "$HOME/.coredns" on Unix, but it's location can be overridden with the COREDNSPATH
-// environment variable.
-var CoreDir = dir(fsPath())
-
-func (d dir) Zone(z string) dir {
-	if z != "." && z[len(z)-2] == '.' {
-		return dir(path.Join(string(d), "D"+z[:len(z)-1]))
-	}
-	return dir(path.Join(string(d), "D"+z))
-}
-
-// fsPath returns the path to the directory where the application may store data.
-// If COREDNSPATH env variable. is set, that value is used. Otherwise, the path is
-// the result of evaluating "$HOME/.coredns".
-func fsPath() string {
-	if corePath := os.Getenv("COREDNSPATH"); corePath != "" {
-		return corePath
-	}
-	return filepath.Join(userHomeDir(), ".coredns")
-}
-
-// userHomeDir returns the user's home directory according to environment variables.
-//
-// Credit: http://stackoverflow.com/a/7922977/1048862
-func userHomeDir() string {
-	if runtime.GOOS == "windows" {
-		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
-		if home == "" {
-			home = os.Getenv("USERPROFILE")
-		}
-		return home
-	}
-	return os.Getenv("HOME")
-}

middleware/pkg/storage/fs_test.go

-package storage
-
-import (
-	"os"
-	"path"
-	"strings"
-	"testing"
-)
-
-func TestFsPath(t *testing.T) {
-	if actual := fsPath(); !strings.HasSuffix(actual, ".coredns") {
-		t.Errorf("Expected path to be a .coredns folder, got: %v", actual)
-	}
-
-	os.Setenv("COREDNSPATH", "testpath")
-	defer os.Setenv("COREDNSPATH", "")
-	if actual, expected := fsPath(), "testpath"; actual != expected {
-		t.Errorf("Expected path to be %v, got: %v", expected, actual)
-	}
-}
-
-func TestZone(t *testing.T) {
-	for _, ts := range []string{"example.org.", "example.org"} {
-		d := CoreDir.Zone(ts)
-		actual := path.Base(string(d))
-		expected := "D" + ts
-		if actual != expected {
-			t.Errorf("Expected path to be %v, got %v", actual, expected)
-		}
-	}
-}
-
-func TestZoneRoot(t *testing.T) {
-	for _, ts := range []string{"."} {
-		d := CoreDir.Zone(ts)
-		actual := path.Base(string(d))
-		expected := "D" + ts
-		if actual != expected {
-			t.Errorf("Expected path to be %v, got %v", actual, expected)
-		}
-	}
-}