Remove unused osd_test.cpp and mock/ringloop.h, move epmgr out of osd_t

src/test/mock/ringloop.h

@@ -1,31 +0,0 @@
-// Copyright (c) Vitaliy Filippov, 2019+
-// License: VNPL-1.1 or GNU GPL-2.0+ (see README.md for details)
-
-#pragma once
-
-#include <functional>
-
-struct ring_consumer_t
-{
-    std::function<void(void)> loop;
-};
-
-class ring_loop_t
-{
-public:
-    void register_consumer(ring_consumer_t *consumer)
-    {
-    }
-    void unregister_consumer(ring_consumer_t *consumer)
-    {
-    }
-    void submit()
-    {
-    }
-    void wait()
-    {
-    }
-    void loop()
-    {
-    }
-};