Bug 16517: Do not crash when creating a list with an existing name

Bug 16517: Do not crash when creating a list with an existing name

A typo has been made during a merge conflict when rebasing bug 16517.

it should be
  eval { Koha::Object->new->store; };
instead of
  eval { Koha::Object->new; }->store;

Test plan:
From the result list (intranet side), check some entries and add them to
a new list
Use an existing list's name
=> Without this patch you will get a server error (exception 'Duplicate shelf
object' raised by Koha::Virtualshelf->new->store)
=> With this patch you must get a friendly error message

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>