Do cleanup decrypted env secrets files (#1304)

* Do cleanup decrypted env secrets files

Resolves #503

pkg/state/create_test.go

@@ -3,6 +3,7 @@ package state
 import (
 	"github.com/roboll/helmfile/pkg/remote"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"reflect"
 	"testing"
@@ -19,7 +20,9 @@ func createFromYaml(content []byte, file string, env string, logger *zap.Sugared
 		logger:   logger,
 		readFile: ioutil.ReadFile,
 		abs:      filepath.Abs,
-		Strict:   true,
+
+		DeleteFile: os.Remove,
+		Strict:     true,
 	}
 	return c.ParseAndLoad(content, filepath.Dir(file), file, env, true, nil)
 }