package/exiv2: annotate CVE-2019-13504

CVE-2019-13504 is misclassified (by our CVE tracker) as affecting
version 0.27.2, while in fact both commits that fixed this issue are
already in this version: bd0afe039043 and 54f0bebca032.

(From: https://security-tracker.debian.org/tracker/CVE-2019-13504

)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>