Bug 21590: change virtual shelf to list in send list email.

Bug 21590: change virtual shelf to list in send list email.

To test

1) Choose a public list from the 'lists' menu in the OPAC.
2) Click 'Send list'
3) Log in as necessary
4) Fill in your own email address
5) Click 'send'
6) Check your email, the sent email will contain the text
   "sent you from our online catalog, the virtual shelf called".

Apply patch, re-test. The email will now contain
   "sent you from our online catalog, the list called".

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>