fix bug in LOG for flush memtable
fix bug in LOG for flush memtable

Summary:
  One line change to fix a bug in the LOG when flush memtable

Test Plan:
  NONE

Reviewers: sdong

Reviewed By: sdong

Differential Revision: https://reviews.facebook.net/D20049

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