tests: Fix coverity warnings

Assorted minor code issues, which we should fix so any new errors stand
out more.

BUG=chromium:643769
BRANCH=none
TEST=make runtests

Change-Id: I927571f8a30794c70228506afe4da3eda86f765b
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/383953
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
15 files changed