Consult experts about an SRV for the next time period and whether that means we should upload HsDescs for the next time period

See #1166 (closed).

We need to ask @dgoulet (Hi, David!) about what to do when we have an SRV for the next time period and we are thinking about uploading an HsDesc for a time period that has not started yet. Is this possible? We think that we've run into it.