Bugfixes for tiering

Fixed a few issues that manifested during the tiering tests,

    1) When a version is copied, it now contains copies of the levels,
       not just pointers (the levels themselves still hold pointers to
       the shards, though).
    2) Ensure that tasks are scheduled with the correct timestamp, they
       were originally being scheduled backwards. The get_merge_tasks()
       method already returns them in the correct order, so reversing
       them again put it in the wrong order.

0 files changed, 0 insertions, 0 deletions