Wrong commit message in source browser with re-added files (BB-1641)

Wrong commit message on re-added files.

{{{
$ echo test > testfile
$ hg add
adding testfile
$ hg ci -m "first commit"
$ hg push
pushing to xxx
......
yyy is allowed. accepted payload.

$ hg rm testfile
$ hg ci -m "removed"
$ hg push
pushing to xxx
......
yyy is allowed. accepted payload.

$ echo test > testfile
$ hg add
adding testfile
$ hg ci -m "re-add"
$ hg push
pushing to xxx
......
yyy is allowed. accepted payload.
}}}

And then, source browser shows "first commit" message instead of "re-add" message on testfile.