Bug 22114: Untranslatable "Patron note:" in checkout.js

Bug 22114: Untranslatable "Patron note:" in checkout.js

This patch modifies JavaScript used in circulation, replacing an
untranslatable English string in the script with a variable defined in
strings.inc which can be translated.

To test you should have the AllowCheckoutNotes system preference
enabled.

 - Apply the patch and log in to the OPAC as a user who has two or more
   items checked out.
 - From the list of checkouts on the "Your summary" page, add a note to
   two or more checked-out items.
 - Log in to the staff client and open the checkout page for that user.
   - In the table of checkouts, check the "Check in" checkbox next to
     one of the titles you added a note to.
   - Click "Renew or check in selected items."
   - A message should appear in that table row showing your note,
     prefixed with the text "Patron note:"

To test translation, update and install the de-DE template:

 > cd misc/translator
 > perl translate update de-DE
 > perl translate install de-DE

 - Go to Administration -> System preferences and enable the "Deutsch
   (de-DE)" language under I18N/L10N preferences -> language.
 - Switch to the "Deutsch" translation.
 - Go to Ausleihe (Circulation) and check out to the same patron.
   - In the table of checkouts, check the checkbox in the "Rückgabe"
     column next to another title you added a note to.
   - Click the "Markierte Exemplare zurückgeben oder verlängern" button.
   - A message should appear in that table row showing your note
     prefixed with the text "Benutzernotizen:"

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>