[btcsuite/btcwallet] b74a6f: Update for txscript.Script -> txscript.Engine.

[Josh Rickmar]

  Branch: refs/heads/master
  Home:   https://github.com/btcsuite/btcwallet
  Commit: b74a6f78a609d7a2fc5d450a4eb758e718cf9205
      
https://github.com/btcsuite/btcwallet/commit/b74a6f78a609d7a2fc5d450a4eb758e718cf9205
  Author: Josh Rickmar <jr...@conformal.com>
  Date:   2015-04-20 (Mon, 20 Apr 2015)

  Changed paths:
    M rpcserver.go
    M votingpool/withdrawal.go
    M wallet/createtx.go

  Log Message:
  -----------
  Update for txscript.Script -> txscript.Engine.