rocksdb: update reference to the latest version of clang dev in fbcode
rocksdb: update reference to the latest version of clang dev in fbcode

Summary: Updated reference to the latest clang dev in fbcode. Since RocksDB already uses recent version of clang dev no code changes need.

Test Plan:
Make sure can be build with clang.
```lang=bash
% USE_CLANG=1 make all
```

Reviewers: meyering, sdong, rven, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D35121

norton/rocksdb,anagav/rocksdb,vashstorm/rocksdb,tsheasha/rocksdb,jalexanderqed/rocksdb,NickCis/rocksdb,tizzybec/rocksdb,JohnPJenkins/rocksdb,hobinyoon/rocksdb,tizzybec/rocksdb,tizzybec/rocksdb,OverlordQ/rocksdb,RyanTech/rocksdb,mbarbon/rocksdb,vashstorm/rocksdb,vashstorm/rocksdb,luckywhu/rocksdb,zhangpng/rocksdb,NickCis/rocksdb,sorphi/rocksdb,sorphi/rocksdb,kaschaeffer/rocksdb,ylong/rocksdb,RyanTech/rocksdb,kaschaeffer/rocksdb,wat-ze-hex/rocksdb,siddhartharay007/rocksdb,siddhartharay007/rocksdb,anagav/rocksdb,makelivedotnet/rocksdb,lgscofield/rocksdb,skunkwerks/rocksdb,tizzybec/rocksdb,kaschaeffer/rocksdb,dkorolev/rocksdb,biddyweb/rocksdb,dkorolev/rocksdb,zhangpng/rocksdb,amyvmiwei/rocksdb,sorphi/rocksdb,hobinyoon/rocksdb,norton/rocksdb,caijieming-baidu/rocksdb,IMCG/RcoksDB,fengshao0907/rocksdb,norton/rocksdb,siddhartharay007/rocksdb,wat-ze-hex/rocksdb,biddyweb/rocksdb,wskplho/rocksdb,rDSN-Projects/rocksdb.replicated,flabby/rocksdb,NickCis/rocksdb,wskplho/rocksdb,jalexanderqed/rocksdb,fengshao0907/rocksdb,vmx/rocksdb,biddyweb/rocksdb,Vaisman/rocksdb,amyvmiwei/rocksdb,sorphi/rocksdb,caijieming-baidu/rocksdb,flabby/rocksdb,facebook/rocksdb,makelivedotnet/rocksdb,Applied-Duality/rocksdb,SunguckLee/RocksDB,facebook/rocksdb,ylong/rocksdb,facebook/rocksdb,lgscofield/rocksdb,caijieming-baidu/rocksdb,mbarbon/rocksdb,OverlordQ/rocksdb,mbarbon/rocksdb,IMCG/RcoksDB,wlqGit/rocksdb,fengshao0907/rocksdb,skunkwerks/rocksdb,amyvmiwei/rocksdb,wskplho/rocksdb,bbiao/rocksdb,JackLian/rocksdb,vmx/rocksdb,Andymic/rocksdb,wlqGit/rocksdb,sorphi/rocksdb,anagav/rocksdb,temicai/rocksdb,SunguckLee/RocksDB,flabby/rocksdb,wskplho/rocksdb,biddyweb/rocksdb,mbarbon/rocksdb,temicai/rocksdb,wenduo/rocksdb,vashstorm/rocksdb,SunguckLee/RocksDB,mbarbon/rocksdb,ryneli/rocksdb,wenduo/rocksdb,biddyweb/rocksdb,OverlordQ/rocksdb,NickCis/rocksdb,luckywhu/rocksdb,wat-ze-hex/rocksdb,caijieming-baidu/rocksdb,ylong/rocksdb,JackLian/rocksdb,facebook/rocksdb,tizzybec/rocksdb,virtdb/rocksdb,JoeWoo/rocksdb,JackLian/rocksdb,OverlordQ/rocksdb,facebook/rocksdb,Vaisman/rocksdb,vashstorm/rocksdb,JackLian/rocksdb,anagav/rocksdb,RyanTech/rocksdb,ryneli/rocksdb,norton/rocksdb,ylong/rocksdb,wskplho/rocksdb,JoeWoo/rocksdb,luckywhu/rocksdb,hobinyoon/rocksdb,vmx/rocksdb,wenduo/rocksdb,virtdb/rocksdb,tsheasha/rocksdb,dkorolev/rocksdb,IMCG/RcoksDB,JohnPJenkins/rocksdb,norton/rocksdb,tsheasha/rocksdb,fengshao0907/rocksdb,makelivedotnet/rocksdb,jalexanderqed/rocksdb,facebook/rocksdb,caijieming-baidu/rocksdb,virtdb/rocksdb,tizzybec/rocksdb,norton/rocksdb,wenduo/rocksdb,makelivedotnet/rocksdb,vmx/rocksdb,Andymic/rocksdb,anagav/rocksdb,Vaisman/rocksdb,rDSN-Projects/rocksdb.replicated,jalexanderqed/rocksdb,tsheasha/rocksdb,RyanTech/rocksdb,wskplho/rocksdb,JackLian/rocksdb,Andymic/rocksdb,bbiao/rocksdb,temicai/rocksdb,temicai/rocksdb,wat-ze-hex/rocksdb,kaschaeffer/rocksdb,alihalabyah/rocksdb,biddyweb/rocksdb,Vaisman/rocksdb,kaschaeffer/rocksdb,anagav/rocksdb,SunguckLee/RocksDB,SunguckLee/RocksDB,IMCG/RcoksDB,SunguckLee/RocksDB,JohnPJenkins/rocksdb,geraldoandradee/rocksdb,luckywhu/rocksdb,vmx/rocksdb,amyvmiwei/rocksdb,wlqGit/rocksdb,rDSN-Projects/rocksdb.replicated,ryneli/rocksdb,Vaisman/rocksdb,wenduo/rocksdb,virtdb/rocksdb,vmx/rocksdb,OverlordQ/rocksdb,RyanTech/rocksdb,anagav/rocksdb,rDSN-Projects/rocksdb.replicated,tsheasha/rocksdb,biddyweb/rocksdb,Applied-Duality/rocksdb,bbiao/rocksdb,kaschaeffer/rocksdb,Andymic/rocksdb,dkorolev/rocksdb,IMCG/RcoksDB,alihalabyah/rocksdb,vashstorm/rocksdb,IMCG/RcoksDB,rDSN-Projects/rocksdb.replicated,makelivedotnet/rocksdb,virtdb/rocksdb,alihalabyah/rocksdb,tsheasha/rocksdb,skunkwerks/rocksdb,caijieming-baidu/rocksdb,OverlordQ/rocksdb,JackLian/rocksdb,flabby/rocksdb,sorphi/rocksdb,wlqGit/rocksdb,siddhartharay007/rocksdb,tizzybec/rocksdb,RyanTech/rocksdb,lgscofield/rocksdb,wenduo/rocksdb,norton/rocksdb,facebook/rocksdb,JohnPJenkins/rocksdb,luckywhu/rocksdb,luckywhu/rocksdb,geraldoandradee/rocksdb,wskplho/rocksdb,alihalabyah/rocksdb,fengshao0907/rocksdb,bbiao/rocksdb,zhangpng/rocksdb,alihalabyah/rocksdb,OverlordQ/rocksdb,siddhartharay007/rocksdb,NickCis/rocksdb,makelivedotnet/rocksdb,fengshao0907/rocksdb,lgscofield/rocksdb,lgscofield/rocksdb,vmx/rocksdb,lgscofield/rocksdb,JohnPJenkins/rocksdb,ryneli/rocksdb,temicai/rocksdb,hobinyoon/rocksdb,jalexanderqed/rocksdb,siddhartharay007/rocksdb,NickCis/rocksdb,bbiao/rocksdb,Applied-Duality/rocksdb,Applied-Duality/rocksdb,temicai/rocksdb,siddhartharay007/rocksdb,sorphi/rocksdb,jalexanderqed/rocksdb,flabby/rocksdb,facebook/rocksdb,zhangpng/rocksdb,hobinyoon/rocksdb,JohnPJenkins/rocksdb,bbiao/rocksdb,JackLian/rocksdb,dkorolev/rocksdb,zhangpng/rocksdb,vashstorm/rocksdb,Applied-Duality/rocksdb,JoeWoo/rocksdb,ryneli/rocksdb,mbarbon/rocksdb,ryneli/rocksdb,dkorolev/rocksdb,wat-ze-hex/rocksdb,amyvmiwei/rocksdb,luckywhu/rocksdb,hobinyoon/rocksdb,flabby/rocksdb,amyvmiwei/rocksdb,geraldoandradee/rocksdb,Vaisman/rocksdb,wlqGit/rocksdb,hobinyoon/rocksdb,ylong/rocksdb,kaschaeffer/rocksdb,wenduo/rocksdb,wenduo/rocksdb,mbarbon/rocksdb,tsheasha/rocksdb,skunkwerks/rocksdb,geraldoandradee/rocksdb,Applied-Duality/rocksdb,ylong/rocksdb,skunkwerks/rocksdb,IMCG/RcoksDB,alihalabyah/rocksdb,SunguckLee/RocksDB,virtdb/rocksdb,zhangpng/rocksdb,norton/rocksdb,ylong/rocksdb,Andymic/rocksdb,caijieming-baidu/rocksdb,rDSN-Projects/rocksdb.replicated,bbiao/rocksdb,Applied-Duality/rocksdb,JoeWoo/rocksdb,geraldoandradee/rocksdb,Andymic/rocksdb,wlqGit/rocksdb,wat-ze-hex/rocksdb,Andymic/rocksdb,lgscofield/rocksdb,bbiao/rocksdb,RyanTech/rocksdb,skunkwerks/rocksdb,Vaisman/rocksdb,SunguckLee/RocksDB,wlqGit/rocksdb,flabby/rocksdb,zhangpng/rocksdb,geraldoandradee/rocksdb,JohnPJenkins/rocksdb,jalexanderqed/rocksdb,fengshao0907/rocksdb,JoeWoo/rocksdb,wat-ze-hex/rocksdb,skunkwerks/rocksdb,temicai/rocksdb,ryneli/rocksdb,vmx/rocksdb,JoeWoo/rocksdb,dkorolev/rocksdb,tsheasha/rocksdb,virtdb/rocksdb,amyvmiwei/rocksdb,Andymic/rocksdb,NickCis/rocksdb,rDSN-Projects/rocksdb.replicated,wat-ze-hex/rocksdb,makelivedotnet/rocksdb,geraldoandradee/rocksdb,hobinyoon/rocksdb,JoeWoo/rocksdb,alihalabyah/rocksdb