Handle errors reading battery status on android differently.

During one run, we apparently couldn't read the battery status from
the device properly, and then crashed trying to parse the output.

This patch corrects the behavior to mark the device as unusable, but
the underlying problem presumably will still exist.

TBR=peter@chromium.org
BUG=322167

Review URL: https://codereview.chromium.org/81263005

git-svn-id: svn://svn.chromium.org/blink/trunk@162491 bbb929c8-8fbe-4397-9dbb-9b2b20218538