[Rocksdb] Log on disable/enable file deletions
[Rocksdb] Log on disable/enable file deletions

Summary: as title

Test Plan: compile

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D11085

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