Crash during deserialisation of of protocol magic, when it's too large to fit `int32`.

[deepfire]

Whenever nodes are configured with a value of protocol magic too large to fit int32, this makes the receiving side crash.

https://github.com/input-output-hk/ouroboros-network/blob/master/ouroboros-consensus/src/Ouroboros/Consensus/Ledger/Byron.hs#L780

Sep 12 15:24:40 a-node 3xihbn4f05nyd2q38sk8ylr0xiszww26-unit-script-cardano-node_-start[21794]: cardano-node: ExceptionInLinkedThread "ThreadId 43" annotateBoundary: serialization roundtrip failure: DeserialiseFailure 2 "expected int32"
Sep 12 15:24:40 a-node 3xihbn4f05nyd2q38sk8ylr0xiszww26-unit-script-cardano-node_-start[21794]: CallStack (from HasCallStack):
Sep 12 15:24:40 a-node 3xihbn4f05nyd2q38sk8ylr0xiszww26-unit-script-cardano-node_-start[21794]:   error, called at src/Ouroboros/Consensus/Ledger/Byron.hs:780:7 in ouroboros-consensus-0.1.0.0-EEi65UrUq7lCWnkSf1LDCN:Ouroboros.Consensus.Ledger.Byron

This is as per:

• cardano-ledger 22363162ee08039ec6158c24a0882c9357e9e35e
• ouroboros-network 05a62ac

[mrBliss]

The correct line: https://github.com/input-output-hk/ouroboros-network/blob/05a62acdd64405e284d54a94d55cda832855a84e/ouroboros-consensus/src/Ouroboros/Consensus/Ledger/Byron.hs#L780

[edsko]

@deepfire We can just outlaw this right? Or is there a reason why larger protocol magic might be needed?