Put errenous blocks into Redis as well

[icook]

For the frontend to be more aware of problems occuring in powerpool, it would be nice for stale/reject/errored blocks of any kind to be still placed in redis with a flag indicating that there was a problem. For instance, in an unlikely race condition a DOGE block was orphaned at just the right time to cause it to have a "total_subsidy" of 0. This should have the error flag set, so the frontend doesn't try to process the bad data still.