failure detection for parallel dependencies

[robert-chiniquy]

when dependencies load in parallel and one fails while another is still loading, the failure of the first won't be noticed when the second succeeds:

# dependencies
ok 855 agent_endpoint_2 started in 18ms
ok 856 agent_endpoint_secure_2 started in 205ms
not ok 857 agent_endpoint_2 exited with code 7
  ---
    operator: fail
    at: ChildProcess.<anonymous> (/data/ele/node_modules/depends-on/index.js:222:14)
  ...
Killing noit because agent_endpoint_2 exited with code 7
Killing cassandra because agent_endpoint_2 exited with code 7
Killing zookeeper because agent_endpoint_2 exited with code 7
Killing public_api because agent_endpoint_2 exited with code 7
Killing admin_api because agent_endpoint_2 exited with code 7
Killing internal_api because agent_endpoint_2 exited with code 7
Killing cep because agent_endpoint_2 exited with code 7
Killing messenger because agent_endpoint_2 exited with code 7
Killing agent_endpoint_1 because agent_endpoint_2 exited with code 7
Killing agent_endpoint_secure_1 because agent_endpoint_2 exited with code 7
Killing agent_endpoint_secure_2 because agent_endpoint_2 exited with code 7
Killing agent_endpoint_3 because agent_endpoint_2 exited with code 7
Killing test_notification_server because agent_endpoint_2 exited with code 7
Killing mock_email_api because agent_endpoint_2 exited with code 7
Killing mock_customer_api because agent_endpoint_2 exited with code 7
Killing mock_identity_api because agent_endpoint_2 exited with code 7
Killing blueflood because agent_endpoint_2 exited with code 7
Killing usage_publisher because agent_endpoint_2 exited with code 7
Killing warehouser because agent_endpoint_2 exited with code 7
Killing cep_test because agent_endpoint_2 exited with code 7
Killing mock_blueflood_query because agent_endpoint_2 exited with code 7
Killing cloud_metrics_public_api because agent_endpoint_2 exited with code 7
Killing mock_upgrade_service because agent_endpoint_2 exited with code 7
Killing ele_traceroute_service because agent_endpoint_2 exited with code 7
ok 858 agent_endpoint_3 started in 9481ms
ok 859 agent_endpoint_3 started in 9497ms
ok 860 agent_endpoint_secure_3 started in 210ms
ok 861 Dependencies start up after 9772 ms
# initialize
Error: connect ECONNREFUSED
    at errnoException (net.js:904:11)
    at Object.afterConnect [as oncomplete] (net.js:895:19)