Null response from DistQuery::Rewards when there are no rewards

[baedrik]

When a secret contract attempts to do the Rewards query from the Distribution module like follows (where delegator is the HumanAddr whose rewards you want to view):

    let rewards_resp: RewardsResponse = deps.querier.query(&QueryRequest::Dist(DistQuery::Rewards {
       delegator,
    }))?;

If the delegator does not have any pending rewards, the query returns a null response which causes a parse error. Instead it should always return a valid RewardsResponse, but when there are no rewards, the rewards and total fields should be empty Vecs.

[assafmo]

@liorbond is this fixed in v1.4?