R1:fe6022cd97f5

Load only valid properties in LiskDAO::loadFromArray()

Summary:
Fixes a TODO, and silences a warning introduced by D3601.

There are several cases where we load data like:

SELECT *, ... AS extraData FROM ...

...and then pass it to `loadAllFromArray()`. Currently, this causes us to set an `extraData` property on the object.

This idiom seems fairly useful and non-dangerous, so I made `loadFromArray()` just drop extra keys.

Since we hit this loop a potentially huge number of times (10,000+ for full…