runs too quickly to ensure all commit-checks pass

[travi]

from my observations, this appears to be a result of checks being registered after the PR being opened sometimes taking longer to be registered than the time it takes for greenkeeper-keeper to execute.

this manifests in a few different end results:

• the PR is accepted before the check gets registered. the ci build typically fails because the branch gets deleted before the build can pull the code (previous issue: merges "stopped" builds kkemple/greenkeeper-keeper#45)
• greenkeeper-keeper already confirmed that all registered checks passed, but is then blocked from accepting the PR because the newly registered check is now pending

there does not appear to be a way to know which checks would register after a PR is opened until after they have the time to register themselves

[travi]

an example of the list of statuses:

Statuses

  "statuses": [
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076443100,
      "state": "success",
      "description": "Dependencies checked",
      "target_url": "https://dependencyci.com/builds/167884",
      "context": "dependency-ci",
      "created_at": "2017-03-13T07:00:04Z",
      "updated_at": "2017-03-13T07:00:04Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076443762,
      "state": "success",
      "description": "No failing files.",
      "target_url": "https://www.bithound.io/github/travi/travi-api/63d79f4c120e838c3d632543c91bd2c12d74438e/files?status=passing",
      "context": "bitHound - Code",
      "created_at": "2017-03-13T07:00:38Z",
      "updated_at": "2017-03-13T07:00:38Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076443763,
      "state": "success",
      "description": "No failing dependencies.",
      "target_url": "https://www.bithound.io/github/travi/travi-api/63d79f4c120e838c3d632543c91bd2c12d74438e/dependencies/npm?status=passing",
      "context": "bitHound - Dependencies",
      "created_at": "2017-03-13T07:00:38Z",
      "updated_at": "2017-03-13T07:00:38Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076443804,
      "state": "success",
      "description": "Greenkeeper verified pull request",
      "target_url": "https://greenkeeper.io/verify.html",
      "context": "greenkeeper/verify",
      "created_at": "2017-03-13T07:00:40Z",
      "updated_at": "2017-03-13T07:00:40Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076444800,
      "state": "success",
      "description": "No known vulnerabilities found",
      "target_url": "https://nodesecurity.io/orgs/travi/projects/2f6e0dcc-a394-4789-95a9-226c1f8d7d27/428",
      "context": "Node Security",
      "created_at": "2017-03-13T07:01:34Z",
      "updated_at": "2017-03-13T07:01:34Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076444883,
      "state": "success",
      "description": "No new vulnerabilities",
      "target_url": "https://snyk.io/test/github/travi/travi-api/63d79f4c120e838c3d632543c91bd2c12d74438e?fromStatus=true",
      "context": "security/snyk",
      "created_at": "2017-03-13T07:01:38Z",
      "updated_at": "2017-03-13T07:01:38Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076445473,
      "state": "success",
      "description": "The Travis CI build passed",
      "target_url": "https://travis-ci.org/travi/travi-api/builds/210460129",
      "context": "continuous-integration/travis-ci/push",
      "created_at": "2017-03-13T07:02:10Z",
      "updated_at": "2017-03-13T07:02:10Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076446873,
      "state": "success",
      "description": "The Travis CI build passed",
      "target_url": "https://travis-ci.org/travi/travi-api/builds/210460448",
      "context": "continuous-integration/travis-ci/pr",
      "created_at": "2017-03-13T07:03:30Z",
      "updated_at": "2017-03-13T07:03:30Z"
    },
    {
      "url": "https://api.github.com/repos/travi/travi-api/statuses/63d79f4c120e838c3d632543c91bd2c12d74438e",
      "id": 1076446880,
      "state": "success",
      "description": "Coverage remained the same at 100.0%",
      "target_url": "https://coveralls.io/builds/10558779",
      "context": "coverage/coveralls",
      "created_at": "2017-03-13T07:03:31Z",
      "updated_at": "2017-03-13T07:03:31Z"
    }
  ],