[conformal/btcwire] 2c1923: Update fastsha256 import paths to new location.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcwire
  Commit: 2c1923897dd73ff227065ba05479f780675121b8
      
https://github.com/conformal/btcwire/commit/2c1923897dd73ff227065ba05479f780675121b8
  Author: Dave Collins <da...@conformal.com>
  Date:   2015-01-16 (Fri, 16 Jan 2015)

  Changed paths:
    M common.go

  Log Message:
  -----------
  Update fastsha256 import paths to new location.