[mechanisms] fix python exe name in siconos_mechanisms script
[mechanisms] fix python exe name in siconos_mechanisms script

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