DataNode: `min_key_` not set.

[stoianmihail]

Hi,

The variable max_key_ is set several times in alex_nodes.h. On the other hand, min_key_ is updated only in insert (missing in both bulk_loads). I just wanted to make sure that this is the intended behavior (and why).

Thanks!
Mihail.

[jialinding]

Seems to me like a bug. Thanks for pointing it out! Would you like to make a PR that sets min_key_ during bulk load? If not, I can do it myself.

[stoianmihail]

I've just created one. Let me know if there's anything else I should add to the PR.