remove client passive move

[kofemann]

The original dcap implementation was based on a model where dcache pool connect to the client for the data path. Now days so called passive mode is preferred, where client initializes both control and data connections, as this is more firewall friendly behavior. The old functionality is mostly not used and/or source of unexpected problems, thus should be removed.

[kofemann]

@ellert I suggest we drop old behavior and bump client version to 2.48.0