lnodes: fix buggy conditional.

I was thought I was testing

  if ((eside->is_hanging && eside->is.hanging.quad[0] &&
      eside->is.hanging.quad[1]) ||
      (!eside->is_hanging && eside->is.full.quad)) {
    // ...
  }

but what I had was

  if ((eside->is_hanging && eside->is.hanging.quad[0] &&
      eside->is.hanging.quad[1]) ||
      eside->is.full.quad) {
    // ...
  }

It turns out we can completely skip the hanging case, and it works
correctly: there is always a full side with a quadrant present.
libsc update