Bug 7829 - reports/ remove all exit(1) for plack

Bug 7829 - reports/ remove all exit(1) for plack

In Bug 7772 Ian correctly noted that reports have exit(1) all over the place.
This is left over from old code, and this patch changes them to exit(0).

I decided to use plain exit as opposed to explicit exit(0) since it produces
cleaner code, but I'm welcoming suggestion on this.

Signed-off-by: Alex Arnaud <alex.arnaud@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>