Reword support a little bit to more clear and concise
Reword support a little bit to more clear and concise

Summary:
I tried to do this in #1556, but it landed before the change could be imported.
Closes https://github.com/facebook/rocksdb/pull/1557

Differential Revision: D4214572

Pulled By: siying

fbshipit-source-id: 718d4a4

vmx/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,SunguckLee/RocksDB,bbiao/rocksdb,Andymic/rocksdb,Andymic/rocksdb,bbiao/rocksdb,wat-ze-hex/rocksdb,wat-ze-hex/rocksdb,bbiao/rocksdb,wat-ze-hex/rocksdb,vmx/rocksdb,Andymic/rocksdb,bbiao/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,SunguckLee/RocksDB,SunguckLee/RocksDB,bbiao/rocksdb,wat-ze-hex/rocksdb,wat-ze-hex/rocksdb,SunguckLee/RocksDB,bbiao/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,Andymic/rocksdb,Andymic/rocksdb,vmx/rocksdb,bbiao/rocksdb,wat-ze-hex/rocksdb,bbiao/rocksdb,vmx/rocksdb,wat-ze-hex/rocksdb,vmx/rocksdb,wat-ze-hex/rocksdb