clean functions do no longer work due to change in nodes del plugin

Description from this (http://stackoverflow.com/questions/32770896/nodes-del-command-callback-not-firing) Stackoverflow question:
"The callback on the del function is not firing. The del function is running, file are deleted, I see no error messages. If I call the callback manually it executes, so looks like the function is in tact. So I am wondering what would cause del not to want to execute the callback."

This seems to be the solution:
"The [del] API now returns a promise instead of accepting a callback function."
https://github.com/sindresorhus/del/releases/tag/v2.0.0