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.

LOCK(pfrom->cs_filter);
            if (pfrom->pfilter)
                pfrom->pfilter->insert(vData);
            else
            {
                LOCK(cs_main);
                Misbehaving(pfrom->GetId(), 100);
            }
        }
    }
    else if (strCommand == NetMsgType::FILTERCLEAR)
    {
        LOCK(pfrom->cs_filter);
        delete pfrom->pfilter;
        pfrom->pfilter = new CBloomFilter();
        pfrom->fRelayTxes = true;
    }
    else if (strCommand == NetMsgType::REJECT)
    {
        if (fDebug) {
            try {
                string strMsg; unsigned char ccode; string strReason;
                vRecv >> LIMITED_STRING(strMsg, CMessageHeader::COMMAND_SIZE) >> ccode >> LIMITED_STRING(strReason, MAX_REJECT_MESSAGE_LENGTH);
                ostringstream ss;
                ss << strMsg << " code " << itostr(ccode) << ": " << strReason;
                if (strMsg == NetMsgType::BLOCK || strMsg == NetMsgType::TX)
                {
                    uint256 hash;
                    vRecv >> hash;
                    ss << ": hash " << hash.ToString();