Add functions dentry_security and inode_security for accessing
inode->i_security.  These functions initially don't do much, but they
will later be used to revalidate the security labels when necessary.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>