checkpatch post-commit hook

[Alison Schofield <amsfield22@gmail.com>]

I'm thinking of adding a git post-commit hook to our First Patch Tutorial.

Recently, Joe Perches (checkpatch author) showed us a spelling error
in a log message found by checkpatch and it made me realize we may be
under-utilizing checkpatch in the workflow as defined in the first patch
tutorial.

If you use it pre-commit (and while working a file) it shows you
issues in your files.  But, if you use it on the built patch, you
can also see WARNINGS like:

WARNING: Do not use whitespace before Signed-off-by:
WARNING: please write a paragraph that describes the config symbol fully
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?

Here's a post commit hook: 

.git/hooks$ cat post-commit
#!/bin/sh
exec git show HEAD | scripts/checkpatch.pl --nosummary

If someone will verify this and agree we should add it - I'll add it to
the first patch tutorial.

And, of course, you'll let me know if there's another/better way
to do it!

alisons