Interval problem with Repository.iter_fnames()

[b2m]

The method Repository.iter_fnames() accepts the keyword arguments begin and end. When begin and end are in the same interval, the method will yield nothing. Or to use the illustration from the docstring:

Files:            A                 B 
Frames:    |---------------|---------------|
               ⬆      ⬆
             begin   end

Instead of A no filename is yielded.

[nebw]

fixed in de5c84f