Also trap OSError when running lspci.
Also trap OSError when running lspci.

While lspci returning non-zero raises CalledProcessError (like on Raspberry Pi),
the fact it's not present raises OSError (like on Crouton/ARM).

The next one that says exceptions are awesome is better to get out of my way
right now.

R=vadimsh@chromium.org
BUG=

Review URL: https://codereview.appspot.com/145780043

madecoste/swarming,pombreda/swarming,luci/luci-py,pombreda/swarming,luci/luci-py,pombreda/swarming,madecoste/swarming,luci/luci-py,madecoste/swarming,pombreda/swarming,madecoste/swarming,luci/luci-py