As segwit is active on testnet, blocks will only be downloaded from NODE_WITNESS peers. Though, exactly those peers are disconnected after `BLOCK_STALLING_TIMEOUT = 2` seconds. I am running master (6e6ab2c)

This behavior is consistent across restarts. Sample [debug.log](http://pastebin.ubuntu.com/23058327/) and [getchaintips](http://pastebin.ubuntu.com/23058325/).

It is possible that I shot my own foot at some point, but it seemed smelly enough to create an issue.

{
                PrintExceptionContinue(&e, "ProcessMessages()");
            }
        }
        catch (const boost::thread_interrupted&) {
            throw;
        }
        catch (const std::exception& e) {
            PrintExceptionContinue(&e, "ProcessMessages()");
        } catch (...) {
            PrintExceptionContinue(NULL, "ProcessMessages()");
        }
        if (!fRet)
            LogPrintf("%s(%s, %u bytes) FAILED peer=%d\n", __func__, SanitizeString(strCommand), nMessageSize, pfrom->id);
        break;
    }
    
    if (!pfrom->fDisconnect)
        pfrom->vRecvMsg.erase(pfrom->vRecvMsg.begin(), it);
    return fOk;
}
class CompareInvMempoolOrder
{
    CTxMemPool *mp;
public:
    CompareInvMempoolOrder(CTxMemPool *mempool)
    {
        mp = mempool;
    }
    bool operator()(std::set<uint256>::iterator a, std::set<uint256>::iterator b)