[AUDIT] add session id to audit messages

In order to correlate audit records to an individual login add a session
id.  This is incremented every time a user logs in and is included in
almost all messages which currently output the auid.  The field is
labeled ses=  or oses=

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 819a6f9..fced6bc 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1905,11 +1905,12 @@
 		if (!!values[i] != policydb.bool_val_to_struct[i]->state) {
 			audit_log(current->audit_context, GFP_ATOMIC,
 				AUDIT_MAC_CONFIG_CHANGE,
-				"bool=%s val=%d old_val=%d auid=%u",
+				"bool=%s val=%d old_val=%d auid=%u ses=%u",
 				policydb.p_bool_val_to_name[i],
 				!!values[i],
 				policydb.bool_val_to_struct[i]->state,
-				audit_get_loginuid(current));
+				audit_get_loginuid(current),
+				audit_get_sessionid(current));
 		}
 		if (values[i]) {
 			policydb.bool_val_to_struct[i]->state = 1;