ScyllaDB release: version 1.4.3

ScyllaDB version 1.4.3, released by the ScyllaDB team in December 2016, is a bugfix update for the 1.4 stable branch, maintaining backward compatibility and supporting rolling upgrades. The release addresses several issues, including a bug with Systemd on CentOS 7.3 that prevented ScyllaDB from starting, a core dump problem during service shutdown, and a housekeeping service that failed to restart its timer upon ScyllaDB restarts. Additionally, the release corrects a kernel check documentation URL error. Contributions to this release come from multiple developers, each tackling specific areas such as systemd and component probing. The update process involved both bug fixes and code reverts to ensure system stability and functionality.