HDDS-4579. Add acceptance test for Ozone Client Key Validator

[adoroszlai]

What changes were proposed in this pull request?

1. Add acceptance test for key validator (freon ockv).
2. Make current Freon robot test (of generators) reusable by setting prefix from parameter instead of random one.
3. Remove freon rk from this reusable test.
   a. it's already exercised in other tests
   b. it's also being deprecated in favor of newer generators
4. Remove useless Wait Until Keyword Succeeds from Freon robot test: no point in repeating the Should contain check every 10 second since ${result} is not updated.
5. Exercise Freon robot test in upgrade environment instead of more "manual" steps from topology test. This allows us to test generator+validator both before and after upgrade (post-upgrade generator can be enabled with/after HDDS-4562).
6. Fix the bug that re-loading testlib.sh defines invalid OM_HA_PARAM for non-HA OM setup. It happens because empty OM_SERVICE_ID is set to om the first time, which makes testlib.sh think it's HA in the second round.

https://issues.apache.org/jira/browse/HDDS-4579

How was this patch tested?

cd hadoop-ozone/dist/target/ozone-1.1.0-SNAPSHOT/compose/upgrade
./test.sh

https://github.com/adoroszlai/hadoop-ozone/runs/1537554565?check_suite_focus=true#step:7:1732
https://github.com/adoroszlai/hadoop-ozone/runs/1537554565?check_suite_focus=true#step:7:1742
https://github.com/adoroszlai/hadoop-ozone/runs/1537554565?check_suite_focus=true#step:7:1815

[captainzmc]

+1, LGTM. Thanks for the patch.

[adoroszlai]

Thanks @captainzmc for reviewing and committing it.