smack-setup: enable Smack/CIPSO mapping

smack-setup: enable Smack/CIPSO mapping

CIPSO is the Common IP Security Option, an IETF standard for setting
security levels for a process sending packets. In Smack kernels,
CIPSO headers are mapped to Smack labels automatically, but can be changed.

This patch writes label/category mappings from /etc/smack/cipso/ to
/sys/fs/smackfs/cipso2. The mapping format is "%s%4d%4d"["%4d"]...

For more information about Smack and CIPSO, see:
  https://kernel.org/doc/Documentation/security/Smack.txt