Add some missing comments.
Add some missing comments.

ok @davecgh

mathiasrw/btcd,1d4Nf6/btcd,ppcsuite/ppcd,glv2/ppcd,ppcsuite/ppcd,soapboxsys/ombfullnode,DanielKrawisz/btcd,cqswxj2013/btcd,sysbot/btcd,qchain/btcd,stevenroose/btcd,dajohi/btcd,danoctavian/btcd,BitGo/prova,runeaune/btcd,jrick/btcd,Stash-Crypto/btcd,cjepson/btcd,ltcsuite/ltcd,Cleawing/btcd,jrick/dcrd,jimmysong/btcd,Cleawing/btcd,Stash-Crypto/btcd,btcsuitereleases/btcd,CryptocurrencyCabal/htcd,toddfries/btcd,stevenroose/btcd,btcsuite/btcd,DanielKrawisz/btcd,FactomProject/btcd,jongillham/btcd,ppcsuite/ppcd-old,jimmysong/btcd,Dirbaio/btcd,wallclockbuilder/btcd,Roasbeef/btcd,Roasbeef/btcd,qchain/btcd,jcmincke/dcrd,cqswxj2013/btcd,adiabat/btcd,davecgh/btcd,dajohi/btcd,BitGo/prova,jcmincke/dcrd,soapboxsys/ombfullnode,toddfries/btcd,davecgh/btcd,decred/dcrd,dan-da/btcd,decred/dcrd,glv2/ppcd,tb00/btcd,danoctavian/btcd,sysbot/btcd,1d4Nf6/btcd,ltcsuite/ltcd,FactomProject/btcd,pkothbauer/btcd,jrick/dcrd,wallclockbuilder/btcd,btcsuite/btcd,jongillham/btcd,mathiasrw/btcd,Dirbaio/btcd,jrick/btcd,dajohi/btcd,adiabat/btcd,jcmincke/dcrd,pkothbauer/btcd,aakselrod/btcd,cjepson/btcd,tb00/btcd,runeaune/btcd,btcsuitereleases/btcd,Dirbaio/btcd,CryptocurrencyCabal/htcd,aakselrod/btcd,jrick/btcd,hectorj/btcd,ppcsuite/ppcd-old,hectorj/btcd,dan-da/btcd