message: simplify deleting vectors in destructor
diff: @@ -62,8 +62,10 @@ SlepcEigenSolver::SlepcEigenSolver(MPI_Comm comm, const std::string &prefix)
  SlepcEigenSolver::~SlepcEigenSolver()
  {
  - if (VR) { delete VR; }
  - if (VC) { delete VC; }
  + delete VR;
  + delete VC;
  + VR = VC = NULL;
  +
  MPI_Comm comm;
  ierr = PetscObjectGetComm((PetscObject)eps,&comm); PCHKERRQ(eps,ierr);
  ierr = EPSDestroy(&eps); CCHKERRQ(comm,ierr);
  