fix OOIION-1290

https://jira.oceanobservatories.org/tasks/browse/OOIION-1290
The change is rather straightforward; besides the PR, see the Jira for additional details.

Submitting PR mainly for reviewing purposes.

A key test, which continues to run Ok is:
ion/services/sa/observatory/test/test_platform_status.py:Test.test_platform_status_terminate_and_restart_instrument_1_1

@MauriceManning please review
@jamie-cyber1 please review