Bug 8604: Patron cards made for patrons which don't have patron images use preceding...

Bug 8604: Patron cards made for patrons which don't have patron images use preceding card's image

This patch corrects referential problems which caused the script to
"re-use" images as well as other sorts of bad image behaviour.

To test:

1. Ensure that you can reproduce the original bug or some variation thereof
using the steps described in either of these two comments:

    https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=8604#c0

    https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=8604#c6

    NOTE: This is not an easy bug to reproduce.

2. Once you can reproduce the bug, apply this patch and follow the same steps
used to reproduce the bug.

3. Observe that the symptoms are corrected.

Signed-off-by: Chris Nighswonger <cnighswonger@foundations.edu>
Signed-off-by: Christian Stelzenmüller <christian.stelzenmueller@bsz-bw.de>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Reproduced the bug and resolved it with this patch.
Code is hard to read; exact cause of the problem was not fully uncovered.

Fixed spelling 'Destory' => 'Destroy'

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>