message: Fix bug in ParGridFunction::ProjectDiscCoefficient
  Calling parallel assemble is conceptually wrong, since a GridFunction
  represents also vdofs. See
  Suggested-by: Veselin Dobrev
diff: @@ -367,10 +367,10 @@ void ParGridFunction::ProjectDiscCoefficient(Coefficient &coeff, AvgType type)
  GroupCommunicator &gcomm = pfes->GroupComm();
  gcomm.Reduce<int>(zones_per_vdof, GroupCommunicator::Sum);
  gcomm.Bcast(zones_per_vdof);
  - // Accumulate for all tdofs.
  - HypreParVector *tv = this->ParallelAssemble();
  - this->Distribute(tv);
  - delete tv;
  +
  + // Accumulate for all vdofs.
  + gcomm.Reduce(data, GroupCommunicator::Sum);
  + gcomm.Bcast(data);
  ComputeMeans(type, zones_per_vdof);
  }
  @@ -389,10 +389,10 @@ void ParGridFunction::ProjectDiscCoefficient(VectorCoefficient &vcoeff,
  GroupCommunicator &gcomm = pfes->GroupComm();
  gcomm.Reduce<int>(zones_per_vdof, GroupCommunicator::Sum);
  gcomm.Bcast(zones_per_vdof);
  - // Accumulate for all tdofs.
  - HypreParVector *tv = this->ParallelAssemble();
  - this->Distribute(tv);
  - delete tv;
  +
  + // Accumulate for all vdofs.
  + gcomm.Reduce(data, GroupCommunicator::Sum);
  + gcomm.Bcast(data);
  ComputeMeans(type, zones_per_vdof);
  }
  