Queue API response should not include error builds

[josephharrington]

The logic to get the build queue looks like:

    def active_builds(self):
        """
        Returns a list of incomplete builds
        :rtype: list[Build]
        """
        return [build for build in self.builds() if not build.is_finished]

The build.is_finished property includes the CANCELED state but not the ERROR state. This leads to the /queue API returning any build that ever ran that ended in ERROR state.

I'd like to get rid of build.is_finished entirely and have calling logic specify exact build states.

[josephharrington]

This also causes at least one functional test to wait unnecessarily during tearDown. test_failed_setup_does_not_kill_slave intentionally creates a build that fails with an error. When the functional test framework hits tearDown it attempts to wait until the master service's queue is empty, but that will never happen since this error build is present. This is a minor problem that adds a few seconds to test execution and causes a misleading error to be printed even though the test still passes:

test_failed_setup_does_not_kill_slave (test.functional.test_cluster_basic.TestClusterBasic) ... [2017-07-10 17:55:11.623] 67156 INFO    MainThread      functional_test Waiting on build queue to become empty.
[2017-07-10 17:55:12.634] 67156 INFO    MainThread      functional_test Waiting on build queue to become empty.
[2017-07-10 17:55:13.644] 67156 INFO    MainThread      functional_test Waiting on build queue to become empty.
[2017-07-10 17:55:14.653] 67156 INFO    MainThread      functional_test Waiting on build queue to become empty.
[2017-07-10 17:55:15.662] 67156 INFO    MainThread      functional_test Waiting on build queue to become empty.
[2017-07-10 17:55:16.666] 67156 ERROR   MainThread      functional_test Master queue did not become empty before timeout. Last queue response: {'child_routes': {},
 'queue': [{'details': '0 of 5 subjobs are complete (0.0%).',
            'error_message': 'Setup failed on this build more than 5 '
                             'times. Failing the build.',
            'failed_atoms': None,
            'id': 1,
            'num_atoms': None,
            'num_subjobs': 5,
            'request_params': {'build_project_directory': '/tmp/clusterrunner_build_symlinks/30abd5a8-7fd5-4174-955f-acb37ef9472f',
                               'config': {'atomizers': [{'TOKEN': 'seq '
                                                                  '0 4'}],
                                          'commands': ['echo $TOKEN'],
                                          'setup_build': ['exit 1']},
                               'project_directory': '/var/folders/22/q4nt_p514pg4v4szxf7dd0t88_wkq9/T/tmppvntjm7x',
                               'type': 'directory'},
            'result': None,
            'state_timestamps': {'building': 1499734511.380225,
                                 'canceled': 1499734511.508467,
                                 'error': 1499734511.508844,
                                 'finished': None,
                                 'prepared': 1499734511.367606,
                                 'preparing': 1499734511.352481,
                                 'queued': 1499734511.350816},
            'status': 'ERROR'}]}
[2017-07-10 17:55:16.666] 67156 NOTICE  MainThread      functional_test Gracefully killing process with pid 68213...
[2017-07-10 17:55:16.703] 67156 NOTICE  MainThread      functional_test Gracefully killing process with pid 68221...
ok