message: fix reversing of track Px in propagator
diff: @@ -198,8 +198,7 @@ GPUd() int AliHLTTPCGMPropagator::RotateToAlpha( float newAlpha )
  c[ 8] *= j1;
  }
  - if( px1 <0 ){ // change direction
  - t0.SetDirectionAlongX();
  + if( t0.SetDirectionAlongX() ){ // change direction if Px < 0
  fT->SinPhi() = -fT->SinPhi();
  fT->DzDs() = -fT->DzDs();
  fT->QPt() = -fT->QPt();
  