Add Seccomp-BPF policies to the repo.

These policies can be used with the Minijail tool
(http://git.chromium.org/gitweb/?p=chromiumos/platform/minijail.git)
to achieve kernel attack surface reduction.

(Also fix some trailing whitespace.)

BUG=chromium-os:36653
TEST=None

Change-Id: I35dd74702f7dfd701c86e1b25b0831d3925fbf96
Signed-off-by: Jorge Lucangeli Obes <jorgelo@chromium.org>