Improve error return from sendrawtransaction.
Improve error return from sendrawtransaction.

Rather than simply returning "TX rejected" to the RPC client which
submitted a sendrawtransaction that fails, include the reason the it
failed.

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