* ns2: add tc TC_mirror_unitdata_tx_status_blocked
* ns: add test case for SIZE after a successful configuration
* ns: add test case for UNITDATA transmission
* ns: fix missing f_ prefix for function f_tx_block_by_vty
* ns: always clean up the ns_codec
* ns: add tests to test UNITDATA over a BLOCKED nsvcs
* ns: add TC_sns_sgsn_size_correct_port to check if SIZE_ACK is transmitted from the correct port
* ns: f_init_vty: only reset SNS configuration when using SNS.
* ns: add TC_sns_bss_remove_bind_fail_sns to check SNS fails correct when removing a bind