Clarify emptyIncludeConf logic
Clarify emptyIncludeConf logic

Suggestion from John Newbery <john@johnnewbery.com> in
https://github.com/bitcoin/bitcoin/pull/15934#discussion_r343795528

mruddy/bitcoin,ahmedbodi/vertcoin,EthanHeilman/bitcoin,fujicoin/fujicoin,jambolo/bitcoin,pataquets/namecoin-core,lateminer/bitcoin,AkioNak/bitcoin,AkioNak/bitcoin,jnewbery/bitcoin,alecalve/bitcoin,MarcoFalke/bitcoin,instagibbs/bitcoin,peercoin/peercoin,alecalve/bitcoin,GroestlCoin/bitcoin,GroestlCoin/bitcoin,tecnovert/particl-core,GroestlCoin/GroestlCoin,practicalswift/bitcoin,n1bor/bitcoin,alecalve/bitcoin,ahmedbodi/vertcoin,Sjors/bitcoin,GroestlCoin/GroestlCoin,cdecker/bitcoin,vertcoin/vertcoin,qtumproject/qtum,kallewoof/bitcoin,peercoin/peercoin,EthanHeilman/bitcoin,pataquets/namecoin-core,sipsorcery/bitcoin,achow101/bitcoin,lateminer/bitcoin,jonasschnelli/bitcoin,prusnak/bitcoin,fujicoin/fujicoin,jonasschnelli/bitcoin,anditto/bitcoin,Sjors/bitcoin,MarcoFalke/bitcoin,cdecker/bitcoin,namecoin/namecore,DigitalPandacoin/pandacoin,jamesob/bitcoin,particl/particl-core,fujicoin/fujicoin,instagibbs/bitcoin,achow101/bitcoin,rnicoll/dogecoin,pstratem/bitcoin,mitchellcash/bitcoin,rnicoll/bitcoin,litecoin-project/litecoin,tjps/bitcoin,practicalswift/bitcoin,namecoin/namecore,litecoin-project/litecoin,instagibbs/bitcoin,qtumproject/qtum,apoelstra/bitcoin,monacoinproject/monacoin,tjps/bitcoin,ajtowns/bitcoin,tecnovert/particl-core,cdecker/bitcoin,pstratem/bitcoin,JeremyRubin/bitcoin,prusnak/bitcoin,qtumproject/qtum,bitcoinsSG/bitcoin,litecoin-project/litecoin,litecoin-project/litecoin,rnicoll/bitcoin,fanquake/bitcoin,achow101/bitcoin,mm-s/bitcoin,EthanHeilman/bitcoin,ajtowns/bitcoin,practicalswift/bitcoin,litecoin-project/litecoin,yenliangl/bitcoin,mitchellcash/bitcoin,monacoinproject/monacoin,tecnovert/particl-core,MeshCollider/bitcoin,sipsorcery/bitcoin,domob1812/bitcoin,midnightmagic/bitcoin,fanquake/bitcoin,apoelstra/bitcoin,jlopp/statoshi,practicalswift/bitcoin,domob1812/namecore,kallewoof/bitcoin,prusnak/bitcoin,apoelstra/bitcoin,JeremyRubin/bitcoin,vertcoin/vertcoin,mm-s/bitcoin,namecoin/namecoin-core,rnicoll/bitcoin,achow101/bitcoin,sipsorcery/bitcoin,lateminer/bitcoin,rnicoll/dogecoin,Xekyo/bitcoin,n1bor/bitcoin,JeremyRubin/bitcoin,bitcoinsSG/bitcoin,domob1812/namecore,jambolo/bitcoin,JeremyRubin/bitcoin,JeremyRubin/bitcoin,Xekyo/bitcoin,apoelstra/bitcoin,namecoin/namecore,ajtowns/bitcoin,andreaskern/bitcoin,lateminer/bitcoin,tjps/bitcoin,pstratem/bitcoin,gjhiggins/vcoincore,pstratem/bitcoin,anditto/bitcoin,jnewbery/bitcoin,kallewoof/bitcoin,ElementsProject/elements,DigitalPandacoin/pandacoin,GroestlCoin/GroestlCoin,mitchellcash/bitcoin,mruddy/bitcoin,andreaskern/bitcoin,jamesob/bitcoin,rnicoll/bitcoin,n1bor/bitcoin,vertcoin/vertcoin,mitchellcash/bitcoin,sipsorcery/bitcoin,fujicoin/fujicoin,sipsorcery/bitcoin,achow101/bitcoin,jonasschnelli/bitcoin,MeshCollider/bitcoin,bitcoinknots/bitcoin,sstone/bitcoin,ajtowns/bitcoin,dscotese/bitcoin,mm-s/bitcoin,DigitalPandacoin/pandacoin,apoelstra/bitcoin,Xekyo/bitcoin,lateminer/bitcoin,sstone/bitcoin,cdecker/bitcoin,midnightmagic/bitcoin,Xekyo/bitcoin,MeshCollider/bitcoin,dscotese/bitcoin,sstone/bitcoin,yenliangl/bitcoin,ahmedbodi/vertcoin,JeremyRubin/bitcoin,bitcoin/bitcoin,domob1812/namecore,andreaskern/bitcoin,peercoin/peercoin,domob1812/bitcoin,lateminer/bitcoin,EthanHeilman/bitcoin,mruddy/bitcoin,prusnak/bitcoin,andreaskern/bitcoin,instagibbs/bitcoin,jnewbery/bitcoin,pataquets/namecoin-core,qtumproject/qtum,jamesob/bitcoin,mruddy/bitcoin,fanquake/bitcoin,bitcoinsSG/bitcoin,jlopp/statoshi,gjhiggins/vcoincore,ElementsProject/elements,litecoin-project/litecoin,n1bor/bitcoin,ahmedbodi/vertcoin,pataquets/namecoin-core,Sjors/bitcoin,ElementsProject/elements,ahmedbodi/vertcoin,monacoinproject/monacoin,achow101/bitcoin,practicalswift/bitcoin,rnicoll/dogecoin,andreaskern/bitcoin,gjhiggins/vcoincore,sstone/bitcoin,namecoin/namecore,mm-s/bitcoin,Sjors/bitcoin,midnightmagic/bitcoin,apoelstra/bitcoin,MarcoFalke/bitcoin,n1bor/bitcoin,dscotese/bitcoin,particl/particl-core,bitcoinknots/bitcoin,domob1812/namecore,fujicoin/fujicoin,midnightmagic/bitcoin,dscotese/bitcoin,bitcoin/bitcoin,bitcoinsSG/bitcoin,bitcoin/bitcoin,domob1812/namecore,andreaskern/bitcoin,MarcoFalke/bitcoin,MeshCollider/bitcoin,qtumproject/qtum,namecoin/namecoin-core,namecoin/namecore,sstone/bitcoin,jonasschnelli/bitcoin,namecoin/namecoin-core,mruddy/bitcoin,peercoin/peercoin,mm-s/bitcoin,AkioNak/bitcoin,mitchellcash/bitcoin,domob1812/namecore,GroestlCoin/bitcoin,prusnak/bitcoin,ElementsProject/elements,alecalve/bitcoin,monacoinproject/monacoin,ElementsProject/elements,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,instagibbs/bitcoin,tecnovert/particl-core,jamesob/bitcoin,bitcoin/bitcoin,jnewbery/bitcoin,Sjors/bitcoin,particl/particl-core,rnicoll/dogecoin,kallewoof/bitcoin,jlopp/statoshi,namecoin/namecoin-core,yenliangl/bitcoin,practicalswift/bitcoin,tecnovert/particl-core,namecoin/namecoin-core,monacoinproject/monacoin,sstone/bitcoin,anditto/bitcoin,jlopp/statoshi,fanquake/bitcoin,jnewbery/bitcoin,jonasschnelli/bitcoin,jambolo/bitcoin,bitcoinknots/bitcoin,pataquets/namecoin-core,MarcoFalke/bitcoin,kallewoof/bitcoin,ajtowns/bitcoin,qtumproject/qtum,bitcoinknots/bitcoin,rnicoll/bitcoin,Xekyo/bitcoin,jambolo/bitcoin,tecnovert/particl-core,fanquake/bitcoin,vertcoin/vertcoin,peercoin/peercoin,jamesob/bitcoin,midnightmagic/bitcoin,bitcoin/bitcoin,GroestlCoin/GroestlCoin,rnicoll/dogecoin,EthanHeilman/bitcoin,mitchellcash/bitcoin,particl/particl-core,gjhiggins/vcoincore,DigitalPandacoin/pandacoin,yenliangl/bitcoin,dscotese/bitcoin,MeshCollider/bitcoin,tjps/bitcoin,yenliangl/bitcoin,particl/particl-core,vertcoin/vertcoin,GroestlCoin/bitcoin,ElementsProject/elements,kallewoof/bitcoin,jlopp/statoshi,rnicoll/bitcoin,n1bor/bitcoin,anditto/bitcoin,jlopp/statoshi,MeshCollider/bitcoin,GroestlCoin/GroestlCoin,gjhiggins/vcoincore,domob1812/bitcoin,pstratem/bitcoin,anditto/bitcoin,namecoin/namecore,bitcoin/bitcoin,prusnak/bitcoin,EthanHeilman/bitcoin,jambolo/bitcoin,vertcoin/vertcoin,GroestlCoin/bitcoin,Xekyo/bitcoin,domob1812/bitcoin,gjhiggins/vcoincore,tjps/bitcoin,cdecker/bitcoin,yenliangl/bitcoin,pataquets/namecoin-core,anditto/bitcoin,instagibbs/bitcoin,jambolo/bitcoin,bitcoinsSG/bitcoin,domob1812/bitcoin,monacoinproject/monacoin,ahmedbodi/vertcoin,AkioNak/bitcoin,midnightmagic/bitcoin,sipsorcery/bitcoin,mruddy/bitcoin,alecalve/bitcoin,tjps/bitcoin,qtumproject/qtum,pstratem/bitcoin,AkioNak/bitcoin,jamesob/bitcoin,GroestlCoin/GroestlCoin,particl/particl-core,alecalve/bitcoin,fanquake/bitcoin,domob1812/bitcoin,dscotese/bitcoin,bitcoinknots/bitcoin,cdecker/bitcoin,peercoin/peercoin,bitcoinsSG/bitcoin,GroestlCoin/bitcoin,AkioNak/bitcoin,ajtowns/bitcoin,MarcoFalke/bitcoin,mm-s/bitcoin,fujicoin/fujicoin,namecoin/namecoin-core