We removed a warning about the channel_update being malformed since
the warning could cause lnd to disconnect (seems they treat
channel-unrelated warnings as fatal?). This was caused by lnd not
enforcing the `htlc_maximum`, thus the parsing would fail. We can
re-add the warning once our assumption that `htlc_maximum` being set
is valid.
Changelog-Fixed: gossip: We no longer send warning that lnd would not understand if we get outdated gossip
e5d384a427