Issue 49381 - Add docstrings to ds_logs, gssapi_repl, betxn
Description: Refactor docstrings of ds_logs, gssapi_repl and betxn test
suites. Also change test_betxn_init to fixure function.
And add pytest.mark.bz numbers.
https://pagure.io/389-ds-base/issue/49381
Reviewed by: Simon Pichugin