mariadb and systemctl

	fix systemctl commands
	change mysql to mariadb
	add aliases for systemctl and firewall-cmd
	misc comments

On branch centos7
Changes to be committed:

	modified:   init.sh
	modified:   scripts/aliases.sh
	modified:   scripts/firewalld.sh
	modified:   scripts/lemp.sh
	modified:   scripts/nginx_config.sh
	modified:   scripts/server_ssh.sh
	modified:   setup.sh