crash: sandbox the sender script a bit

We're a bit limited in what we can pull off here since it's a shell
script and we need to read reports saved under the root account, but
it's better than nothing.

BUG=chromium:766275
TEST=ran by hand and it still was able to process crash reports
TEST=precq passes

Change-Id: I0d3e0c13787c075ede8e2e8ffee8fd66108a0687
Reviewed-on: https://chromium-review.googlesource.com/678294
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed