IGNITE-1681: loadAll threshold is not configurable for CacheStoreBalancingWrapper (MERGED)

[Denis Magda]

Michael,

Thanks a lot for the contribution! I've reviewed and merged your changes
into the release branch.

Please refer to minor comments from me left in the latest post:
https://issues.apache.org/jira/browse/IGNITE-1681


Look forward to new contributions from you!
Denis