roles/mariadb: Change socket location

Instead of using /var/run, just use /run directly. This is the real
path and it's the default anyways.

roles/mariadb/defaults/main.yml

@@ -17,7 +17,7 @@ innodb_buffer_pool_size: 256M
 # Ansible 2.7.x with PyMySQL seems to default to TCP connection so we should
 # force it to use a Unix socket.
 # See: https://github.com/ansible/ansible/issues/47736
-mariadb_login_unix_socket: /var/run/mysqld/mysqld.sock
+mariadb_login_unix_socket: /run/mysqld/mysqld.sock
 
 # default is 100 but the max I've seen used is 5, so let's reduce it
 max_connections: 33

roles/mariadb/templates/my.cnf.j2

@@ -19,14 +19,14 @@
 # Remember to edit /etc/mysql/debian.cnf when changing the socket location.
 [client]
 port		= 3306
-socket		= /var/run/mysqld/mysqld.sock
+socket		= /run/mysqld/mysqld.sock
 
 # Here is entries for some specific programs
 # The following values assume you have at least 32M ram
 
 # This was formally known as [safe_mysqld]. Both versions are currently parsed.
 [mysqld_safe]
-socket		= /var/run/mysqld/mysqld.sock
+socket		= /run/mysqld/mysqld.sock
 nice		= 0
 
 [mysqld]
@@ -34,8 +34,8 @@ nice		= 0
 # * Basic Settings
 #
 user		= mysql
-pid-file	= /var/run/mysqld/mysqld.pid
-socket		= /var/run/mysqld/mysqld.sock
+pid-file	= /run/mysqld/mysqld.pid
+socket		= /run/mysqld/mysqld.sock
 port		= 3306
 basedir		= /usr
 datadir		= /var/lib/mysql