Update .travis.yml to suppress ubuntu 17.04
Update .travis.yml to suppress ubuntu 17.04

Ubuntu 17.04 that reaches its “end of life”
radarsat1/siconos,fperignon/siconos,radarsat1/siconos,bremond/siconos,radarsat1/siconos,siconos/siconos,bremond/siconos,fperignon/siconos,bremond/siconos,radarsat1/siconos,fperignon/siconos,bremond/siconos,fperignon/siconos,fperignon/siconos,siconos/siconos,siconos/siconos,bremond/siconos,siconos/siconos,radarsat1/siconos