Bug 16534: Block AddIssue from issuing if the return is not possible

Bug 16534: Block AddIssue from issuing if the return is not possible

To make sure the return can be done, AddIssue must not trust callers (they
should have done their job, but we are not sure) and check that the issue can
be returned before issuing to the patron.

There is no test plan here, this should not be possible from the Koha
interface.
However, looking at the code, it may be possible using SIP.

Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>