Handle malformed DB data

[MegaRedHand]

See #443 for an example. In decode_live_chain_key we don't check the key length before decoding, leading to a possible panic. We should gracefully handle this.

[dicethedev]

can you assign me this? @MegaRedHand

[MegaRedHand]

You already have 3 issues assigned to you. Finish those first please