Hash index is vcol-based wrapper (MDEV-371). row_end is added to
unique index. So when row_end is updated unique hash index must be
recalculated via vcol_update_fields(). DELETE did not update virtual
fields, so DELETE HISTORY was getting wrong hash value.

The fix does update_virtual_fields() on vers_update_end() so in every
case row_end is updated virtual fields are updated as well.