textproc/zxing-cpp: Patch to remove OpenCV libs from the installed cmake files

net/kitinerary was broken because OpenCV libs were unnecessarily supplied to its build by
cmake files from textproc/zxing-cpp. These OpenCV libs were missing -L/usr/local/lib for
some reason, possiblt because OpenCV's cmake files provide LIBS without -L/usr/local/lib.

PR: 237388
Reported by: Martin Birgmeier <d8zNeCFG@aon.at>