UBUNTU: SAUCE: Audit: Add new record for multiple process LSM attributes

UBUNTU: SAUCE: Audit: Add new record for multiple process LSM attributes

Create a new audit record type to contain the subject information
when there are multiple security modules that require such data.
This record is linked with the same timestamp and serial number.
The record is produced only in cases where there is more than one
security module with a process "context".

Before this change the only audit events that required multiple
records were syscall events. Several non-syscall events include
subject contexts, so the use of audit_context data has been expanded
as necessary.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>