list_entity for entity sets returns MB_TYPE_OUT_OF_RANGE

[Tim Tautges]

Calling Interface::list_entity for an entity set should not return an error code. The reason this is being returned is that there is an underlying call to get_connectivity for the set, which returns that error code. The proper fix is probably to not call get_connectivity if the entity is of type entity set. You don’t see this error reported by running mbsize -ll with a file containing sets because of the issue reported in Issue 129.