convert with filemap, moving into subdirectory

[James Walker]

The online help for the --filemap option of hg convert says "To rename 
from a subdirectory into the root of the repository, use '.' as the path 
to rename to."  I take it that the filemap file would contain something like

   rename subdir .

What if you want to go the other way, move things in the root directory 
down into a subdirectory?  I'd think you should be able to use

   rename . subdir

but it didn't work.  An oversight?