package/zziplib: fix CVE-2018-16548

An issue was discovered in ZZIPlib through 0.13.69. There is a memory
leak triggered in the function __zzip_parse_root_directory in zip.c,
which will lead to a denial of service attack.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>