Remove useless method LatchCounter::sum_deregister()

storage/innobase/include/sync0policy.h

 /*****************************************************************************
 
 Copyright (c) 2013, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -454,14 +454,7 @@ class BlockMutexPolicy
 	void destroy()
 		UNIV_NOTHROW
 	{
-		latch_meta_t&	meta = sync_latch_get_meta(m_id);
-
-		ut_ad(meta.get_id() == m_id);
-
-		meta.get_counter()->sum_deregister(m_count);
-
 		m_count = NULL;
-
 		ut_d(MutexDebug<MutexType>::destroy());
 	}
 

storage/innobase/include/sync0types.h

 /*****************************************************************************
 
 Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, MariaDB Corporation.
+Copyright (c) 2017, 2018, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -640,14 +640,6 @@ class LatchCounter {
 		return(count);
 	}
 
-	/** Deregister the count. We don't do anything
-	@param[in]	count		The count instance to deregister */
-	void sum_deregister(Count* count)
-		UNIV_NOTHROW
-	{
-		/* Do nothing */
-	}
-
 	/** Register a single instance counter */
 	void single_register(Count* count)
 		UNIV_NOTHROW