repoman: tweak myupdates/myheaders commit logic

If we unconditionally exclude myremoved from myupdates, then removed
files will also be excluded from myheaders. This allows us to avoid
unnecessary separate manifest commits in cases when "myheaders" only
contained files that were being removed. Since our code always uses
myupdates + myremoved, this change in logic doesn't break anything.
1 file changed