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).
foo renamed from bar:26d3ca0dfd18e44d796b564e38dd173c9668d3a9
rev offset length base linkrev nodeid p1 p2
0 0 6 0 0 26d3ca0dfd18 000000000000 000000000000
1 6 7 1 1 d267bddd54f7 26d3ca0dfd18 000000000000