Bug 19080: Handle non-existing patrons gratefully

Bug 19080: Handle non-existing patrons gratefully

This is a recurrent bug we have over the last years. When a script is
called with non-existent borrowernumber it will crashes.
We need to handle this gracefully instead of letting the script crashes.

On bug 18403 a new subroutine is added to the codebase
(output_and_exit_if_error) to handle this kind of errors correctly.
Since it is not pushed yet, I propose to just redirect to a script that
handle it correctly (circulation.pl) instead of adding this message to
all these scripts.

Test plan:
Hit different scripts from the members module and pass a non-existent
borrowernumber.
You must be redirected to circulation.pl with a friendly message.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>