Make sure the changelog mentions files whose flags changed
These changes don't actually need a new filelog entry (see next patch),
but if we don't mention the files in the changelog, it becomes much
harder to find all changesets that touch a file (not even a
"hg log --removed file" will work).
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b