Security update for libzypp, zypper (important)

This update for libzypp, zypper fixes the following issues: Update libzypp to version 16.17.20: Security issues fixed: - PackageProvider: Validate delta rpms before caching bsc1091624, bsc1088705, CVE-2018-7685 - PackageProvider: Validate downloaded rpm package signatures before caching bsc109162...