Fix a flappy reaping-faulty-nodes test (#61)
Fix a flappy reaping-faulty-nodes test (#61)

* Fix a flappy reaping-faulty-nodes test

It is not uncommon for SUT to ping an unrelated node with itself saying
"I'm alive". In this test, we need to ignore these pings. The case is
best reproduced with an overloaded system with n > 10. Example output:

    not ok 4979 The gossip should contain a flagged

      ---
        operator: ok
        expected: true
        actual:   false
        at: Array.validateEventBody [as 8] op-node/test/ringpop-common/test/ringpop-assert.js:147:11)
      ...
    ============== error details ===============

    {
      "body": {
        "checksum": 3250656653,
        "changes": [
          {
            "id": "6768c914-06e1-4122-8d00-0a2648f7f86d",
            "address": "127.0.0.1:24935",
            "status": "alive",
            "incarnationNumber": 1464253153302
          }
        ],
        "source": "127.0.0.1:24935",
        "sourceIncarnationNumber": 1464253153302
      }
    }

    ============================================


uber/ringpop-common,uber/ringpop-common,uber/ringpop-common