Update HISTORY for PR8585 (#8623)

Summary:
Update HISTORY.md for PR https://github.com/facebook/rocksdb/issues/8585 .

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8623

Reviewed By: ltamasi

Differential Revision: D30121910

Pulled By: riversand963

fbshipit-source-id: 525af43fad908a498f22ed4f934ec5cbf60e6d25

HISTORY.md

@@ -4,6 +4,7 @@
 * If the primary's CURRENT file is missing or inaccessible, the secondary instance should not hang repeatedly trying to switch to a new MANIFEST. It should instead return the error code encountered while accessing the file.
 * Fixed a race related to the destruction of `ColumnFamilyData` objects. The earlier logic unlocked the DB mutex before destroying the thread-local `SuperVersion` pointers, which could result in a process crash if another thread managed to get a reference to the `ColumnFamilyData` object.
 * Removed a call to `RenameFile()` on a non-existent info log file ("LOG") when opening a new DB. Such a call was guaranteed to fail though did not impact applications since we swallowed the error. Now we also stopped swallowing errors in renaming "LOG" file.
+* Fixed an issue where `OnFlushCompleted` was not called for atomic flush.
 
 ### New Features
 * Made the EventListener extend the Customizable class.