Bug 7631 - Self checkout renewal fails because of reference to non-existent subroutin...

Bug 7631 - Self checkout renewal fails because of reference to non-existent subroutine in sco-main.pl

Changing "CanBookBeIssuedCheckout" to "CanBookBeIssued"

To test, try to renew an item which has no renewals left. Before the patch
you'll get an error:

Undefined subroutine &main::CanBookBeIssuedCheckout called at /opac/sco/sco-main.pl line 135.

After the patch you'll get the correct message about having no renewals left.
Other tests: checking out a barcode which doesn't exist, checking out an
item which is on hold for another patron.

Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>