Bug 13857: Email field for sharing is a bit short

The email field for sharing a list with another patron is
a bit short.

To test:
- Make sure OpacAllowSharingPrivateLists is activated
- Create a list in OPAC
- Use the "Share list" link to share with another user
- Check the length of the email field and if you like it
  better with this patch applied

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit fecffe6ebc)
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>

koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-shareshelf.tt

@@ -52,7 +52,7 @@
             <li><label for="name">List name:</label> [% shelfname %]</li>
             <li>
                 <label for="invite_address">Email address:</label>
-                <input id="invite_address" name="invite_address"/>
+                <input id="invite_address" name="invite_address" size="40" />
             </li>
             </ol>
         </fieldset>