[btcsuite/btcd] 4a397d: peer: Don't log write errs due to disconnect.

[Dave Collins]

  Branch: refs/heads/master
  Home:   https://github.com/btcsuite/btcd
  Commit: 4a397d51d4e25d0fcf445bb9621fd78528ee863c
      
https://github.com/btcsuite/btcd/commit/4a397d51d4e25d0fcf445bb9621fd78528ee863c
  Author: Dave Collins <da...@conformal.com>
  Date:   2015-10-23 (Fri, 23 Oct 2015)

  Changed paths:
    M peer/peer.go

  Log Message:
  -----------
  peer: Don't log write errs due to disconnect.

This commit modifies the peer logging so that it will not log an error
when it's due to the remote peer disconnecting or the peer being
forcibly disconnected or shutdown.