Regression in geo.log messages

Consider:

{"severity":"DEBUG","time":"2018-04-12T00:59:30.346Z","pid":7505,"class":"Lease","message":"Lease obtained. Fetching events."}
{"severity":"DEBUG","time":"2018-04-12T00:59:30.351Z","pid":7505,"class":"Lease","message":"Finished fetching events."}
{"severity":"DEBUG","time":"2018-04-12T00:59:30.352Z","pid":7505,"class":"Lease","message":"Lease renewed."}

In the past, instead of "class":"Lease", we'd see the Geo scheduler worker or the log cursor daemon or some such.

/cc @toon @jramsay