nsqlookupd: fix race on PeerInfo.lastUpdate
nsqd: restore previous error message
nsqd: deflake TestSampling
nsqd: quiet TestBadFin
nsqd: deflake TestClientAttributes
nsqlookupd: deflake TestTombstoneRecover
nsqlookupd: deflake TestInactiveNodes
nsqlookupd: deflake TestTombstonedNodes