Fix warnings reported by cpplint.

This CL fixes the warnings reported by cpplint and converts the code to
use PLOG() instead of calling LOG() with strerror(errno).

BUG=chromium:385849
TEST=Tested the following:
1. `FEATURES=test emerge-$BOARD chromeos-imageburner`
2. `cpplint.py --filter=-build/header_guard,-build/include_order *.h *.cc`

Change-Id: Id0285430747d323a63bbc85df11dd05e06bb32f7
Reviewed-on: https://chromium-review.googlesource.com/204463
Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
12 files changed