USN-8514-2: OpenSSH vulnerability

USN-8514-1 fixed a vulnerability in OpenSSH. This update provides the corresponding fix for Ubuntu 14.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. Original advisory details: It was discovered that OpenSSH incorrectly handled file permissions when downloading files as root using the legacy scp protocol without the preserve-mode option.