audit: use current whenever possible

There are many places, notably audit_log_task_info() and
audit_log_exit(), that take task_struct pointers but in reality they
are always working on the current task.  This patch eliminates the
task_struct arguments and uses current directly which allows a number
of cleanups as well.

Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/integrity/ima/ima_api.c

@@ -336,7 +336,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
 	audit_log_untrustedstring(ab, filename);
 	audit_log_format(ab, " hash=\"%s:%s\"", algo_name, hash);
 
-	audit_log_task_info(ab, current);
+	audit_log_task_info(ab);
 	audit_log_end(ab);
 
 	iint->flags |= IMA_AUDITED;