crash: change sender to use unique /tmp dir

Now that the runtime/test knobs are in /run and not /tmp, we can
set up a unique /tmp path for this script everytime we run it.

BUG=chromium:766275
TEST=precq passes

Change-Id: I6ae974b2f3c82162fe943168b5b63d725bba5660
Reviewed-on: https://chromium-review.googlesource.com/723869
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
1 file changed