Linux Sandbox: move NaCl to new BPF policy format.

Migrate NaCl to the new BPF policies format.

BUG=325535, 267179
R=mseaborn@chromium.org, piman@chromium.org, rsesek@chromium.org

Review URL: https://codereview.chromium.org/110833002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239650 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239650