spatialdb/spatial_db.cc: use !empty() instead of 'size() > 0'
spatialdb/spatial_db.cc: use !empty() instead of 'size() > 0'

Use empty() since it should be prefered as it has, following
the standard, a constant time complexity regardless of the
containter type. The same is not guaranteed for size().

Signed-off-by: Danny Al-Gaaf <473e39ac77cf392f0dd9bacde8409de76c14d006@bisect.de>

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