refinediag rerunning bug

[ceblanton]

Describe the bug
When refinediag is used and the refined history file already exists, FRE is supposed to combine what was in the refined history file with the new refined output.

Instead, the existing output is within a directory within the refined history file.

To Reproduce
Any refinediag use for a segment that already has refined history output will bring this out. So:

1. Run refinediag so that the refined history file exists
2. Do it again
3. Observe the subdirectory within the refined history output. The subdirectory contains the previously generated refine output

Expected behavior
The new refined output should overwrite the old refined output, and there should be no subdirectory within the refined history output.

Additional context
Add any other context about the problem here.