OLMIS-4308, bring concurrency down per-test to 3 VU.
OLMIS-4308, bring concurrency down per-test to 3 VU.

30 turned out to be too much, atm not sure why local testing differed from testing with Jenkins.

OpenLMIS/openlmis-referencedata,OpenLMIS/openlmis-referencedata,OpenLMIS/openlmis-referencedata,OpenLMIS/openlmis-referencedata