Dont force-close on dust exposure if remote reserve is more than dust

[TheBlueMatt]

Just fail the HTLC, force-closing is dumb since we can fail the HTLC ~immediately.

[ariard]

Yes this sounds correct to me if the dust HTLC does not materialize on neither the holder or the counterparty commitment transaction.

[TheBlueMatt]

We should do this, but since it hasn't happened yet, 117.