(fix) deleteing files from the fs or fs adapters was broken, and now is not

[cadriel]

When setting autoCleanup === true for Types.File the admin would error, and files would not be correctly removed from the relevant file system. I tried this against the Azure adapter and the built in FS adapter.

This PR fixes those issues, and seems to work for both adapters fine.

No tests were broken during the course of this change.

  image1: { type: Types.File, autoCleanup: true, storage: azureStorage },
  image2: { type: Types.File, autoCleanup: true, storage: fileStorage },

@wmertens @jossmac @JedWatson