Fix clang warning regarding implicit conversion
Fix clang warning regarding implicit conversion

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