largefiles: commit directories that only contain largefiles (
issue3548)
If we pass a directory to commit whose only commitable files
are largefiles, the core commit code aborts before finding
the largefiles.
So we do the following:
For directories that only have largefiles as matches,
we explicitly add the largefiles to the matchlist and remove
the directory.
In other cases, we leave the match list unmodified.