crash: move runtime flags out of /tmp and into /run

Use a path we fully control all the time so random processes can't
wedge us (albeit for a single boot since /tmp is cleared).

BUG=chromium:766275
TEST=precq passes (which runs autotests that use these flags)
CQ-DEPEND=CL:716878

Change-Id: I88cf97cf96eefc054c040be5c19a27d4e93331b0
Reviewed-on: https://chromium-review.googlesource.com/721564
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
2 files changed