Fix ooiion 1991: platform agents do not re-validate resurrected descendent child agent

Fix https://jira.oceanobservatories.org/tasks/browse/OOIION-1991

@edwardhunter please review and merge.

Test: test_platform_agent_robustness.py:TestPlatformRobustness.test_with_intermediate_subplatform_directly_stopped_then_restarted

Launches a multi-level platform network, then stops one of the intermediate platforms, then re-starts that platform to verify that it gets revalidated for subsequent processing. This is visually verified via the publish_event_for_diagnostics utility, which is called after the stop and then after the re-start. The following is logged out by the parent Node1B platform at those two points:

After the stop of the child:
```
2014-07-08 14:55:36,201 INFO resource_agent-ProcessDefinition_for_PlatformAgent_PlatformAgent_137ddb809934a4282b09f73dd60fc2d26-listen-5 ion.agents.platform.status_manager:1019 'Node1B'/RESOURCE_AGENT_STATE_COMMAND: (624187f8ca88450e89e8e95b0160e816) status report triggered by diagnostic event:
                                           AGGREGATE_COMMS     AGGREGATE_DATA      AGGREGATE_LOCATION  AGGREGATE_POWER
        8108b6fca7ee4bef8eff13a05c790ab8 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        7909ba57578b4de1a441885e15cdaa61 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        8d5ede3469db4f58bb2a6fca3b885630 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        e05954f109fb4e0885233e204d41e3ba : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        20d265d574ae44d0834a0f90c0216dde : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        15c6ffe7121e4f6eaf812bf4abda2338 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        acb3f8aa929b4e898ff763768610f014 : STATUS_UNKNOWN      STATUS_UNKNOWN      STATUS_UNKNOWN      STATUS_UNKNOWN
        1bc677df77604c31ad382b9df70f516b : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        c107f1d1972a44709b388642e4814d23 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        99389c4f25a941bf8e64bc8a7d714183 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        2268ac0ab11341e7b67895dfde6642c3 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        ff03ac66dd194fce85cb21d9fc90d0f3 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
                               aggstatus : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
                           rollup_status : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK

                    invalidated_children : ['acb3f8aa929b4e898ff763768610f014']
```

And then after the re-start of that child:
```
2014-07-08 14:55:50,452 INFO resource_agent-ProcessDefinition_for_PlatformAgent_PlatformAgent_137ddb809934a4282b09f73dd60fc2d26-listen-5 ion.agents.platform.status_manager:1019 'Node1B'/RESOURCE_AGENT_STATE_COMMAND: (624187f8ca88450e89e8e95b0160e816) status report triggered by diagnostic event:
                                           AGGREGATE_COMMS     AGGREGATE_DATA      AGGREGATE_LOCATION  AGGREGATE_POWER
        8108b6fca7ee4bef8eff13a05c790ab8 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        7909ba57578b4de1a441885e15cdaa61 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        8d5ede3469db4f58bb2a6fca3b885630 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        e05954f109fb4e0885233e204d41e3ba : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        20d265d574ae44d0834a0f90c0216dde : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        15c6ffe7121e4f6eaf812bf4abda2338 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        acb3f8aa929b4e898ff763768610f014 : STATUS_UNKNOWN      STATUS_UNKNOWN      STATUS_UNKNOWN      STATUS_UNKNOWN
        1bc677df77604c31ad382b9df70f516b : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        c107f1d1972a44709b388642e4814d23 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        99389c4f25a941bf8e64bc8a7d714183 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        2268ac0ab11341e7b67895dfde6642c3 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
        ff03ac66dd194fce85cb21d9fc90d0f3 : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
                               aggstatus : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK
                           rollup_status : STATUS_OK           STATUS_OK           STATUS_OK           STATUS_OK

                    invalidated_children : []
```