allowDiskUse not supported

[engFelipeMonteiro]

In mocking scenario usually the database is significantly reduced, so the needs os allowDiskUse option is usually not needed, but in production it may be needed, for me it is better that the option don't take effect instead of reasing a exception of no supported.

For better test coverage, it would be good if it doesn't raise a exception.
Follows my workaround this problem:

        if TESTING:
            options = {}
        else:
            options = {"allowDiskUse": True}
        last_operation_fails = operations_col.aggregate(query, **options)