- update to MariaDB 10.2.3
* notable changes:
* HeidiSQL updated to 9.4
* Galera wsrep library updated to 25.3.19
* release notes and changelog:
* https://mariadb.com/kb/en/mariadb/mariadb-1023-release-notes/
* https://mariadb.com/kb/en/mariadb/mariadb-1023-changelog/
* refresh and rename the following patches:
* mariadb-10.1.4-group.patch was renamed to
mariadb-10.2.3-group.patch
* mariadb-10.1.16-systemd-cmake.patch was renamed to
mariadb-10.2.3-systemd-cmake.patch
* mariadb-10.1.18-mysql_install_db-mariadb_dirs.patch was renamed to
mariadb-10.2.3-mysql_install_db-mariadb_dirs.patch

- Replace systemd and systemd-devel BuildRequires with
pkgconfig(libsystemd), which matches what the build system is
actually looking for.

- update to MariaDB 10.1.20
* notable changes:
* XtraDB updated to 5.6.34-79.1
* TokuDB updated to 5.6.34-79.1
* HeidiSQL updated to 9.4
* The limit for the table_open_cache system variable has been increased to 1024K
* Galera wsrep library updated to 25.3.19
* release notes and changelog:
* https://mariadb.com/kb/en/mariadb/mariadb-10120-release-notes/
* https://mariadb.com/kb/en/mariadb/mariadb-10120-changelog/