No --checkpatch documentation; change in default behavior

[Brian Norris]

I noticed that my aiaiai instances are no longer running checkpatch.pl
after I pulled in the latest from your git tree. It seems that this made
checkpatch.pl optional now, and off by default:

    commit 33c41203f0c98ad5eca64d413c75c9cda012d6d1
    Date:   Thu Apr 17 16:27:35 2014 -0700
    aiaiai-test-patchset: make checkpatch optional like other checkers

Also, --checkpatch is not mentioned in the help text.

Can you at least add the appropriate option documentation in the help
text? I would also consider not changing the default behavior like that,
but since your user base is probably not very wide (mostly internal at
Intel?), perhaps this sort of change just deserves a release note (I
realize there is no "release" for this feature yet).

Thanks,
Brian