Check shard config file data against actual shards

[lkatalin]

The shard config data should be a (strict or not) subset of actual shards. That is, it should not contain any treeIDs that don't exist in trillian in reality. We should add a check for this at some point. (It is not a high priority.)

[haydentherapper]

@priyawadhwa @lkatalin Is this still an open task?

[priyawadhwa]

Yep I believe so