Issue with CRC invalid blocks

[martinsumner]

To this end, when we de-serialise a block into a list of KV pairs, we return an empty list if the CRC check fails:

https://github.com/martinsumner/leveled/tree/5bef21d9719a561beeaf735e168bd140d9771e38/src/leveled_sst.erl#L1391-L1399

But when we have an indexed lookup on a block we look at the exact position in the block:

https://github.com/martinsumner/leveled/tree/5bef21d9719a561beeaf735e168bd140d9771e38/src/leveled_sst.erl#L1696-L1697

and this is crashing with the empty list.

Elsewhere in leveled_sst the functions fetchfrom_rawblock/2 and fetchend_rawblock/2 are used to counter this issue.

This issue will cause a database crash on an invalid block - which is not expected.

[martinsumner]

@uwiger

[martinsumner]

https://github.com/martinsumner/leveled/tree/mas-i298-corruptedblocks

This is going through the test cycles now

[martinsumner]

#299

[martinsumner]

EQC test run passed at 1000 tests. Needed to correct issue in eqc test, where it would not accept pause as a valid response to a PUT style request

[martinsumner]

#299