Ignore error in script disassembly for RPC results.
Ignore error in script disassembly for RPC results.

This commit modifies the creation of RPC results to ignore errors in
script disassembly since they already contain the error string inline and
the RPC results must still be generated regardless.

This was already done in the decodescript RPC, however the same thing was
not being done in the higher level verbose transaction results.  This
applies to both the createrawtransaction and decoderawtransaction RPCs.

Also, since this was the only thing that could error within those
functions, the error returns and caller checking of now non-existent
errors have been removed.

Fixes #210.

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