loose the assertion condition of rate_limiter_test
loose the assertion condition of rate_limiter_test

Summary: 0.9 can make the test flaky since just found one test fail with 0.88

Test Plan: make all check

Reviewers: sdong, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63939

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