Bug in CBC ProblemType determination

[Alpar Juttner]

Péter Madarasi reports the following:

Solving a MIP with CBC-vel, if the presolver determined the the problem is infeasible, then CbcMip::type() wrongly returns FEASIBLE.

To fix it, line 391 of cbc.cc should be changed to

else if(_cbc_model->isProvenInfeasible() || _cbc_model->isInitialSolveProvenPrimalInfeasible())
  return INFEASIBLE;