Be: dsbenchmark does not run reliably

For Beryllium jobs

https://jenkins.opendaylight.org/releng/view/controller/job/controller-csit-3node-periodic-benchmark-all-beryllium/168/
https://jenkins.opendaylight.org/releng/view/controller/job/controller-csit-3node-periodic-benchmark-all-beryllium/165/
thre was a problem to run dsbenchmark test.

The rest returned
Error 501, {"errors":{"error":[{"error-type":"application","error-tag":"operation-not-supported","error-message":"No implementation of RPC AbsoluteSchemaPath

{path=[(urn:opendaylight:params:xml:ns:yang:dsbenchmark?revision=2015-01-05)start-test]}

available"}]}}

There are few exceptions in the log files, but they seem to me unrelated to dsbenchmark