package/libarchive: add upstream security fixes

CVE-2019-1000019: Crash when parsing some 7zip archives.

CVE-2019-1000020: A corrupted or malicious ISO9660 image can cause
read_CE() to loop forever.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>