Update btcec.go
Update btcec.go

Updated link to SEC 2: Recommended Elliptic Curve Domain Parameters standard (URL given no longer exists).
ppcsuite/ppcd-old,jimmysong/btcd,Roasbeef/btcd,Stash-Crypto/btcd,ppcsuite/ppcd,jongillham/btcd,Stash-Crypto/btcd,ppcsuite/ppcd-old,btcsuite/btcd,cqswxj2013/btcd,mathiasrw/btcd,danoctavian/btcd,decred/dcrd,toddfries/btcd,hectorj/btcd,jrick/btcd,davecgh/btcd,glv2/ppcd,wallclockbuilder/btcd,jcmincke/dcrd,ltcsuite/ltcd,danoctavian/btcd,jcmincke/dcrd,glv2/ppcd,qchain/btcd,ppcsuite/ppcd,ltcsuite/ltcd,jrick/btcd,jrick/dcrd,Roasbeef/btcd,BitGo/prova,adiabat/btcd,jrick/dcrd,pkothbauer/btcd,aakselrod/btcd,soapboxsys/ombfullnode,btcsuitereleases/btcd,davecgh/btcd,jrick/btcd,soapboxsys/ombfullnode,CryptocurrencyCabal/htcd,Dirbaio/btcd,pkothbauer/btcd,dan-da/btcd,FactomProject/btcd,jimmysong/btcd,Dirbaio/btcd,stevenroose/btcd,aakselrod/btcd,Dirbaio/btcd,dajohi/btcd,jcmincke/dcrd,qchain/btcd,mathiasrw/btcd,tb00/btcd,BitGo/prova,wallclockbuilder/btcd,stevenroose/btcd,DanielKrawisz/btcd,jongillham/btcd,CryptocurrencyCabal/htcd,1d4Nf6/btcd,dajohi/btcd,dajohi/btcd,decred/dcrd,Cleawing/btcd,toddfries/btcd,1d4Nf6/btcd,runeaune/btcd,Cleawing/btcd,adiabat/btcd,tb00/btcd,btcsuitereleases/btcd,FactomProject/btcd,cjepson/btcd,runeaune/btcd,dan-da/btcd,hectorj/btcd,cjepson/btcd,btcsuite/btcd,DanielKrawisz/btcd,cqswxj2013/btcd