update HISTORY.md for DeleteRange bug fix
update HISTORY.md for DeleteRange bug fix

Summary:
fixed in #2799
Closes https://github.com/facebook/rocksdb/pull/2805

Differential Revision: D5734324

Pulled By: ajkr

fbshipit-source-id: a285d4e84bf1018dc2257fd6c3e7c075a7243263

SunguckLee/RocksDB,SunguckLee/RocksDB,bbiao/rocksdb,SunguckLee/RocksDB,SunguckLee/RocksDB,Andymic/rocksdb,bbiao/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,Andymic/rocksdb,Andymic/rocksdb,Andymic/rocksdb,bbiao/rocksdb,Andymic/rocksdb,SunguckLee/RocksDB,bbiao/rocksdb,SunguckLee/RocksDB,bbiao/rocksdb,bbiao/rocksdb,bbiao/rocksdb,Andymic/rocksdb,bbiao/rocksdb