pre-commit.sh: complain about everything
Rearchitect the pre-commit hook a bit so that it checks both
the .topdeps and .topmsg files for problems before exiting
and then shows all detected issues before exiting if any
problems were found.
It's better for users to see all the problems at once rather
than piecemeal and will facilitate introduction of bare mode
support without adding extra overhead.
(Actually it still won't check for dependency issues such as
duplicate, missing or looping unless everything else is okay.
But that's probably a good thing as those are more expensive
checks and are really unrelated to missing/zero-length checks.)
Signed-off-by: Kyle J. McKay <mackyle@gmail.com>