pre-upload: fix json lint to read files from the commit

We shouldn't read files off the current disk, but get all the content
out of git.  This helps with stacked changes and dirty trees.

TEST=unittests pass

Change-Id: I462481aac7711b6994c2aca99253aa0b738157e0
Commit-Ready: Mike Frysinger <>
Tested-by: Mike Frysinger <>
Reviewed-by: Ben Chan <>
2 files changed