Invalid delta>0 assertion in plugins/renepay/mcf.c

[owtyahyg6]

As tested with v24.02.2, the assertion
assert(delta>0)
on line 1412 in plugins/renepay/mcf.c does not always hold, it causes the renepay plugin to crash sometimes. Tested on FreeBSD 14.0-RELEASE-p5 arm64

[Lagrang3]

Hi @owtyahyg6, thanks for reporting on this.

There was a previous issue about that same assertion (#7150), thus this issue might be a duplicate. The fix (#7159) is in the master branch but after version 24.02.2.