Summary:
Release builds are failing on Linux with the error:
```
tools/db_stress.cc: In function ‘int main(int, char**)’:
tools/db_stress.cc:2365:12: error: ‘rocksdb::SyncPoint’ has not been declared
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
            ^
tools/db_stress.cc:2370:12: error: ‘rocksdb::SyncPoint’ has not been declared
   rocksdb::SyncPoint::GetInstance()->SetCallBack(
            ^
tools/db_stress.cc:2375:12: error: ‘rocksdb::SyncPoint’ has not been declared
   rocksdb::SyncPoint::GetInstance()->EnableProcessing();
            ^
make[1]: *** [tools/db_stress.o] Error 1
make[1]: Leaving directory `/data/sandcastle/boxes/trunk-git-rocksdb-public'
make: *** [release] Error 2
```
Closes https://github.com/facebook/rocksdb/pull/2355

Differential Revision: D5113552

Pulled By: sagar0

fbshipit-source-id: 351df707277787da5633ba4a40e52edc7c895dc4