osd: Remove all references to hinfo from optimized EC

osd: Remove all references to hinfo from optimized EC

    Legacy EC used hinfo to store two things:
    1. Shard size
    2. CRCs of the shards

    However:
    * Optimized EC stores different object sizes on each shard
    * Optimized EC scrub calculates the correct sizes of shards and checks them, so shard size checks are not needed in hinfo.
    * Bluestore checks the CRC.
    * Seastore checks the CRC.

    As such, the hinfo object is redundant. As such we remove it in
    optimized EC:

    1. Remove all references/upgrades to hinfo.
    2. Delete hinfo attribute if found on recovery/backfill.
    3. Redirect all scrub references for hinfo to legacy EC.

Signed-off-by: Alex Ainscow <aainscow@uk.ibm.com>