unittests: Fixes unit tests for Windows (part 4)

Currently, there are some unit tests that are failing on Windows due to
various reasons:

- paths not properly joined (filepath.Join should be used).
- files not closed, which means that they cannot be removed / renamed.
- time.Now() is not as precise on Windows, which means that 2
  consecutive calls may return the same timestamp.

pkg/volume/rbd/rbd_unix_test.go

@@ -0,0 +1,37 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rbd
+
+import (
+	"fmt"
+)
+
+func (fake *fakeDiskManager) AttachDisk(b rbdMounter) (string, error) {
+	fake.mutex.Lock()
+	defer fake.mutex.Unlock()
+	fake.rbdMapIndex++
+	devicePath := fmt.Sprintf("/dev/rbd%d", fake.rbdMapIndex)
+	fake.rbdDevices[devicePath] = true
+	return devicePath, nil
+}
+
+func getLoggedSource(devicePath string) (string, error) {
+	return devicePath, nil
+}