pre-upload: split checkpatch check into a hook

BUG=chromium:466264
TEST=`./pre-upload_unittest.py` passes

Change-Id: I2a818745e35d49ed00a165724c1f6cf8acc83b95
Reviewed-on: https://chromium-review.googlesource.com/262395
Reviewed-by: Steve Fung <stevefung@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed