[topogen/topology_writer_imune] use get_map_string() to get map of this session
[topogen/topology_writer_imune] use get_map_string() to get map of this session

Signed-off-by: Robert Wuttke <12e9293ec6b30c7fa8a0926af42807e929c1684f@benocs.com>

Benocs/core,Benocs/core,Benocs/core,Benocs/core,Benocs/core