[io] mechanics_run: fix typo on joints
[io] mechanics_run: fix typo on joints

siconos/siconos,siconos/siconos,siconos/siconos,radarsat1/siconos,radarsat1/siconos,radarsat1/siconos,radarsat1/siconos,siconos/siconos,radarsat1/siconos