Move call to logit() outside a function which has its output redirected.
See next commit for explanation.
The logit calls are moved into a new function LogExcluded(), similar to
LogReadOnly(). I don't see a pretty way to resolve this, so I just went
for the most explicit approach I could think of.
Behaviour change: diff_filecontext will now log *all* excluded paths.
I think that approach is an improvement, because e.g. the fact that `-C`
mode excludes `/home` was not previouslly documented anywhere.
48d425e7c6