audit: fix build break when AUDIT_DEBUG == 2

Looks like this one has been around since 5195d8e2:

	kernel/auditsc.c: In function ‘audit_free_names’:
	kernel/auditsc.c:998: error: ‘i’ undeclared (first use in this function)

...and this warning:

	kernel/auditsc.c: In function ‘audit_putname’:
	kernel/auditsc.c:2045: warning: ‘i’ may be used uninitialized in this function

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>