GitLab

Avoid "error: private field 'last_system_time_' is not used" warnings
which are promoted to errors.  This was somehow triggered by this CL:
https://chromium-review.googlesource.com/973943
(But I'm not sure how- the CL did not remove any direct uses of that
variable.)

Speculative fix applied to the openbsd and freebsd implementations.

TBR=dcheng@chromium.org

Bug: 819289
Change-Id: I862d9c22a8e181ac5dd3f1a644432e5570419a0b
Reviewed-on: https://chromium-review.googlesource.com/979432Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Mostyn Bramley-Moore <mostynb@vewd.com>
Commit-Queue: Mostyn Bramley-Moore <mostynb@vewd.com>
Cr-Commit-Position: refs/heads/master@{#545689}