Bug 23057: If checked_in_ok is set and item is not checked out, alert flag is supress...

Bug 23057: If checked_in_ok is set and item is not checked out, alert flag is supressed for *any* reason

Acknowledgements: Patch also contains original code by David Cook. Patches were squashed for ease of use.

This patch fixes a bug from Bug 15221 and hopefully also makes it so that the alert flag
is suppressed when checked_in_ok is set and an item is not checked out.
To test:
0) Create patron in web interface with a cardnumber and userid of "staff" with a password
that matches the account in SIPconfig.xml. Also set their branch to CPL
(also matching SIPconfig.xml).
1) Create an item with a barcode of 'test'
2) Choose a patron to check out to and record their borrowernumber
In one terminal:
3) cd to your git directory (e.g. /home/koha/koha)
4) perl ./C4/SIP/SIPServer.pm ~/koha-dev/etc/SIPconfig.xml
In another terminal:
5) cd to your git directory (e.g. /home/koha/koha)
6) perl ./misc/sip_cli_emulator.pl -l CPL -su staff -sp <password> --port=6001 --address=localhost --item test -m checkin --patron <borrowernumber>
NOTE: You need to replace <borrowernumber> with the borrowernumber from Step 2, and <password> with the password from Step 0.

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>