Fix an innodb_plugin leak noted in MDEV-11686

buf_flush_init_flush_rbt() was called too early in MariaDB server 10.0,
10.1, MySQL 5.5 and MySQL 5.6. The memory leak has been fixed in
the XtraDB storage engine and in MySQL 5.7.

As a result, when the server is started to initialize new data files,
the buf_pool->flush_rbt will be created unnecessarily and then leaked.
This memory leak was noticed in MariaDB server 10.1 when running the
test encryption.innodb_first_page.

storage/innobase/log/log0recv.cc

@@ -2,6 +2,7 @@
 
 Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2012, Facebook Inc.
+Copyright (c) 2017, MariaDB Corporation. All Rights Reserved.
 
 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
@@ -387,12 +388,6 @@ recv_sys_init(
 	}
 
 #ifndef UNIV_HOTBACKUP
-	/* Initialize red-black tree for fast insertions into the
-	flush_list during recovery process.
-	As this initialization is done while holding the buffer pool
-	mutex we perform it before acquiring recv_sys->mutex. */
-	buf_flush_init_flush_rbt();
-
 	mutex_enter(&(recv_sys->mutex));
 
 	recv_sys->heap = mem_heap_create_typed(256,
@@ -3030,6 +3025,11 @@ recv_recovery_from_checkpoint_start_func(
 	byte*		buf;
 	byte		log_hdr_buf[LOG_FILE_HDR_SIZE];
 	dberr_t		err;
+
+	/* Initialize red-black tree for fast insertions into the
+	flush_list during recovery process. */
+	buf_flush_init_flush_rbt();
+
 	ut_when_dtor<recv_dblwr_t> tmp(recv_sys->dblwr);
 
 #ifdef UNIV_LOG_ARCHIVE