It seems p2p-compactblocks.py fails randomly

From: https://travis-ci.org/bitcoin/bitcoin/jobs/163788152 from #8841
The PR is trivial and totally unrelated to compact block

```
p2p-compactblocks.py:
Initializing test directory /tmp/test3yd_2q3h/2
start_node: bitcoind started, waiting for RPC to come up
start_node: RPC succesfully started
MiniNode: Connecting to Bitcoin Node IP # 127.0.0.1:11016
Testing SENDCMPCT p2p message... 
Testing compactblock headers and shortIDs are correct...
Assertion failed: 
Stopping nodes
Not cleaning up dir /tmp/test3yd_2q3h/2
Failed
stderr:
  File "/home/travis/build/bitcoin/bitcoin/qa/rpc-tests/test_framework/test_framework.py", line 151, in main
    self.run_test()
  File "/home/travis/build/bitcoin/bitcoin/build/../qa/rpc-tests/p2p-compactblocks.py", line 614, in run_test
    self.test_compactblock_construction()
  File "/home/travis/build/bitcoin/bitcoin/build/../qa/rpc-tests/p2p-compactblocks.py", line 264, in test_compactblock_construction
    assert(self.test_node.last_cmpctblock is not None)
Pass: False, Duration: 7 s
```

{
    CInv inv(MSG_TX, tx.GetHash());
    connman.ForEachNode([&inv](CNode* pnode)
    {
        pnode->PushInventory(inv);
    });
}
static void RelayAddress(const CAddress& addr, bool fReachable, CConnman& connman)
{
    int nRelayNodes = fReachable ? 2 : 1; 
    
    
    
    uint64_t hashAddr = addr.GetHash();
    std::multimap<uint64_t, CNode*> mapMix;
    const CSipHasher hasher = connman.GetDeterministicRandomizer(RANDOMIZER_ID_ADDRESS_RELAY).Write(hashAddr << 32).Write((GetTime() + hashAddr) / (24*60*60));
    FastRandomContext insecure_rand;
    auto sortfunc = [&mapMix, &hasher](CNode* pnode) {
        if (pnode->nVersion >= CADDR_TIME_VERSION) {
            uint64_t hashKey = CSipHasher(hasher).Write(pnode->id).Finalize();
            mapMix.emplace(hashKey, pnode);
        }
    };
    auto pushfunc = [&addr, &mapMix, &nRelayNodes, &insecure_rand] {
        for (auto mi = mapMix.begin(); mi != mapMix.end() && nRelayNodes-- > 0; ++mi)
            mi->second->PushAddress(addr, insecure_rand);
    };
    connman.ForEachNodeThen(std::move(sortfunc), std::move(pushfunc));
}
void static ProcessGetData(CNode* pfrom, const Consensus::Params& consensusParams, CConnman& connman)