Looper runp produces default_project_record_identifier folder with an empty stats.yaml

[donaldcampbelljr]

This is a workaround so that looper runp does not fail by not passing a record_identifier to pipestat during the initial pipestat instantiation when outputing results to different result files (stats.yaml).

Unfortunately, it is confusing users, so we should think of a better way to do this:
databio/pepatac#272

[donaldcampbelljr]

This will potentially require major refactoring, so moving to a future milestone. Similar to #425 and #459

[donaldcampbelljr]

Ok, this should now be solved with the upcoming Pipestat v0.9.2 release in tandem with #496