`delphi` endpoint returns wrong result code

[krivard]

When there are no results, Epidata should return

{"result":-2, "message":"no results", "epidata": []}

But for the delphi endpoint, we're returning the following, causing Epidata.check to fail to identify the no-results condition:

$ curl -sL "http://api.covidcast.cmu.edu/epidata/delphi/?system=epic&epiweek=202132"
{"epidata":[],"message":"success","result":1}
$ curl -sL "http://api.covidcast.cmu.edu/epidata/api.php?source=delphi&system=epic&epiweek=202132"
{"epidata":[],"message":"success","result":1}

This in turn is causing excessive (multi-hour) runtimes on some of the nowcasting sensor updates.