USN-5079-2: curl vulnerabilities

USN-5079-1 fixed several vulnerabilities in curl. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. Original advisory details: Patrick Monnerat discovered that curl incorrectly handled upgrades to TLS. When receiving certain responses from servers, curl would continue without TLS even when the option to require a successful upgrade to TLS was specified. (CVE-2021-22946) Patrick Monnerat discovered that curl incorrectly handled responses received before STARTTLS. A remote attacker could possibly use this issue to inject responses...