Bug 11209: Don't sent the same SMS message for the same user the same day

Bug 11209: Don't sent the same SMS message for the same user the same day

For PREDUE messages, one message is sent to the message_queue table for
each items in advance, meaning that the patron could receive duplicate
notices.

The SMS part for DUE and PREDUE often do not contain dynamic parts, only
a standard message.

Note that this patch *only* affects the SMS transport.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>