Serials: Batch Receive interface Copy Location widget was inert

Serials: Batch Receive interface Copy Location widget was inert

Choosing a value from the Copy Location widget wasn't working.  You'd
get a default copy location (or the one supplied by the Receive Unit
Copy Template) no matter what you set that control too.

This is fixed.  One does not read from XUL menulist element by using its
'value' property.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Signed-off-by: Remington Steed <rjs7@calvin.edu>