pahole pointed out that on x86_64 struct audit_context can be rearrainged
to save 16 bytes per struct.  Since we have an audit_context per task this
can acually be a pretty significant gain.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>