Add comment for GetBackupInfo about returned BackupInfos order
Add comment for GetBackupInfo about returned BackupInfos order

Summary: #title

Test Plan: n/a

Reviewers: uddipta, ldemailly, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60393

norton/rocksdb,jalexanderqed/rocksdb,OverlordQ/rocksdb,norton/rocksdb,wat-ze-hex/rocksdb,vmx/rocksdb,facebook/rocksdb,norton/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,hobinyoon/rocksdb,wenduo/rocksdb,wenduo/rocksdb,norton/rocksdb,vmx/rocksdb,Andymic/rocksdb,wat-ze-hex/rocksdb,bbiao/rocksdb,tsheasha/rocksdb,OverlordQ/rocksdb,Andymic/rocksdb,norton/rocksdb,vmx/rocksdb,OverlordQ/rocksdb,OverlordQ/rocksdb,OverlordQ/rocksdb,jalexanderqed/rocksdb,hobinyoon/rocksdb,jalexanderqed/rocksdb,Andymic/rocksdb,tsheasha/rocksdb,bbiao/rocksdb,hobinyoon/rocksdb,facebook/rocksdb,wat-ze-hex/rocksdb,jalexanderqed/rocksdb,ryneli/rocksdb,hobinyoon/rocksdb,wat-ze-hex/rocksdb,wat-ze-hex/rocksdb,facebook/rocksdb,wat-ze-hex/rocksdb,ryneli/rocksdb,vmx/rocksdb,wat-ze-hex/rocksdb,Andymic/rocksdb,Andymic/rocksdb,ryneli/rocksdb,tsheasha/rocksdb,wenduo/rocksdb,SunguckLee/RocksDB,jalexanderqed/rocksdb,hobinyoon/rocksdb,SunguckLee/RocksDB,norton/rocksdb,hobinyoon/rocksdb,tsheasha/rocksdb,SunguckLee/RocksDB,ryneli/rocksdb,tsheasha/rocksdb,vmx/rocksdb,facebook/rocksdb,vmx/rocksdb,SunguckLee/RocksDB,facebook/rocksdb,ryneli/rocksdb,ryneli/rocksdb,jalexanderqed/rocksdb,hobinyoon/rocksdb,Andymic/rocksdb,bbiao/rocksdb,facebook/rocksdb,SunguckLee/RocksDB,Andymic/rocksdb,facebook/rocksdb,bbiao/rocksdb,bbiao/rocksdb,wat-ze-hex/rocksdb,tsheasha/rocksdb,OverlordQ/rocksdb,bbiao/rocksdb,wenduo/rocksdb,SunguckLee/RocksDB,norton/rocksdb,wenduo/rocksdb,wenduo/rocksdb,SunguckLee/RocksDB,wenduo/rocksdb,bbiao/rocksdb,ryneli/rocksdb,wenduo/rocksdb,norton/rocksdb,OverlordQ/rocksdb,tsheasha/rocksdb,jalexanderqed/rocksdb,Andymic/rocksdb,tsheasha/rocksdb,hobinyoon/rocksdb,vmx/rocksdb,bbiao/rocksdb,facebook/rocksdb