It's just a sha256_double, but importantly when we convert it to a
string (in type_to_string, which is used in logging) we use
bitcoin_blkid_to_hex() so it's reversed as people expect.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We were using the bitcoin genesis blockhash for all networks, which is
not correct, and would result in the open being aborted when talking
to other implementations.
Reported-by: @sstone and @pm47
Signed-off-by: Christian Decker <decker.christian@gmail.com>
Like txids, we need to reverse them. We didn't, but then we only used them
to pass to/from bitcoind. We're about to get them from the block header,
so we need to fix that.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>