Bug 3704: SIP Checkin of not checked out item returns error without reason
Checking in an available item returns an error (which is correct) without
giving a reason for the failure as screen_msg (aka AF field in SIP2 is empty).
Based on code suggested by Patrick Langer <patrick.langer@easycheck.org>
Signed-off-by: Ulrich Kleiber <ulrich.kleiber@bsz-bw.de> Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com> Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>