Bug 21257: (bug 13618 follow-up) Handle undef values in JS before escapeHtml call

Bug 21257: (bug 13618 follow-up) Handle undef values in JS before escapeHtml call

To test:
1 - Find an item with no collection or location defined
2 - Check it out to a patron
3 - Note you cannot view the checkouts table
4 - Check the console: TypeError: oObj.collection is null
5 - Apply patch
6 - Restart all the things
7 - Checkouts table should load

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Christopher Brannon <cbrannon@cdalibrary.org>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>