bug_7090: AllowItemsOnHandCheckout syspref

bug_7090: AllowItemsOnHandCheckout syspref

Observe AllowItemsOnHandCheckout syspref when using SIP self checkout

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
To test:
* place an item on hold for patron A
* attempt to circulate that item to patron B (via SIP/selfcheck)
	syspref off: item should not circulate to patron B
	Syspref On: item should circulate to patron B

Both conditions passed in our testing.
Also verified that normal staff client behavior regarding this situation was preserved. It was.

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>
-backported to 3.6.x