We get a label clash: easy, just re-serve:
```
2021-02-18T04:29:37.474Z **BROKEN** plugin-offers: Failed invoice_request lnr1qgsqvgnwgcg35z6ee2h3yczraddm72xrfua9uve2rlrm9deu7xyfzrcyyqwtp0rmsgquvuacqcl5cdfzwzmu3v8tqgvpqs8e80dlmxm7ey4xwrqdsqqqqqqqqqqqqqqqq2pqqfqpqynzqzx9rylzy40ernj4jzc3p2dwy3n8x6lqeaywwk725ghx4kx63pcfxgg2z3nsn80jzge06nt3ks8pr6rvnujq48376lpmrr3cq04nurpy783eyr0awh5773lrlmjek07rjf0nx4g9235ulkcs7jp2h5gumjyquhadh846da3jptxm9g0qz5lne4hjhag for offer 1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67: Got JSON error: {\"code\":900,\"message\":\"Duplicate label\",\"data\":{\"label\":\"1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67-08c5193e2255f91ce5590b110a9ae2466736be0cf48e75bcaa22e6ad8da88709-1\",\"bolt12\":\"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\",\"payment_hash\":\"396250395aa046f4c58162a5ae31952d01bd0c8e5213f32e748ec428a9379cd2\",\"msatoshi\":7700446,\"amount_msat\":\"7700446msat\",\"status\":\"unpaid\",\"description\":\"Weekly coffee for rusty!\",\"expires_at\":1614832137,\"local_offer_id\":\"1cb0bc7b8201c673b8063f4c352270b7c8b0eb02181040f93bdbfd9b7ec92a67\"}}
```
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
As per lastest revision of the spec, we can specify amounts in invoice
requests even if the offer already specifies it, as long as we exceed
the amount given. This allows for tipping, and amount obfuscation.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Means a reshuffle of our logic: we want to multiply by quantity before
conversion for maximum accuracy.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
