[SP-1180] Backport of [PDI-9598] toggling KETTLE_EMPTY_STRING_DIFFERS_FROM_NULL variable has no effect on whether a field is recognized as empty or not empty ("Switch/Case" step)
Merge pull request #398 from stepanovdg/SP-1180

[SP-1180] Backport of [PDI-9598] toggling KETTLE_EMPTY_STRING_DIFFERS_FROM_NULL variable has no effect on whether a field is recognized as empty or not empty ("Switch/Case" step)