Bug 12161: fix regression on serials receiving

Serial receiving was broken when "create an item record when receiving
this serial" is used for the subscription.  This bug was introduced by
the patch for bug 12138.

Signed-off-by: Pasi Kallinen <pasi.kallinen@pttk.fi>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>