[NetLabel]: documentation

Documentation for the NetLabel system, this includes a basic overview
of how NetLabel works, how LSM developers can integrate it into their
favorite LSM, as well as documentation on the CIPSO related sysctl
variables.  Also, due to the difficulty of finding expired IETF
drafts, I am including the IETF CIPSO draft that is the basis of the
NetLabel CIPSO implementation.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index 5f7f7d7..02457ec 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -184,6 +184,8 @@
 	- how to use PPro Memory Type Range Registers to increase performance.
 nbd.txt
 	- info on a TCP implementation of a network block device.
+netlabel/
+	- directory with information on the NetLabel subsystem.
 networking/
 	- directory with info on various aspects of networking with Linux.
 nfsroot.txt