crash: Clean up the temp file used in GetLogContents. On R63, some big log dumps can fill up /tmp and make the OS unstable. R64 won't be affected since it introduces sandboxing and unmounts its own /tmp each time. That said, this CL is still safe for ToT (R64) and needs to land and be baked on R64 before cherry-picked to R63. BUG=chromium:789052 TEST=/tmp is not filled up after repeated crashes. TEST=cros_run_unit_tests --packages crash-reporter Change-Id: I0a54fdac9a150cc37d50f72f6095babb79528bd5 Reviewed-on: https://chromium-review.googlesource.com/798550 Commit-Ready: Kazuhiro Inaba <[email protected]> Tested-by: Kazuhiro Inaba <[email protected]> Reviewed-by: Ilja H. Friedel <[email protected]> Reviewed-by: Mike Frysinger <[email protected]> (cherry picked from commit 7244202cb543ec33fa1e6b3908d05dc30d33d1a8) Reviewed-on: https://chromium-review.googlesource.com/802835 Trybot-Ready: Kazuhiro Inaba <[email protected]> Reviewed-by: Kazuhiro Inaba <[email protected]> Commit-Queue: Kazuhiro Inaba <[email protected]>