Update handleGetBlock to not use deprecated func.
Update handleGetBlock to not use deprecated func.

Rather than using the deprecated TxShas function on a btcutil.Block,
convert handleGetBlock to use the newer preferred method of ranging over
the Transactions to obtain the cached hash of each transaction.

This is a little more efficient since it can avoid creating and caching an
extra slice to keep the hashes in addition to having the hash cached with
each transaction.

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