[conformal/btcd] c7a664: Correct pushGetMerkleBlock throttling.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/conformal/btcd
  Commit: c7a6645ebe5a4d3f46d8e42cfdf8182e25fcc41c
      
https://github.com/conformal/btcd/commit/c7a6645ebe5a4d3f46d8e42cfdf8182e25fcc41c
  Author: Dave Collins <da...@conformal.com>
  Date:   2014-07-10 (Thu, 10 Jul 2014)

  Changed paths:
    M peer.go

  Log Message:
  -----------
  Correct pushGetMerkleBlock throttling.

This commit corrects the check which sends in the done channel when
pushing merkle blocks that have no transactions to go with them.