mariadb: change the group of /var/lib/mysql from 'nogroup' to 'mysql'.

The commit 8f637f9bbc added
mysql group, we should change the group of /var/lib/mysql
from 'nogroup' to 'mysql' also.

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-oe/recipes-support/mysql/mariadb_5.5.38.inc

@@ -123,7 +123,7 @@ pkg_postinst_${PN}-server () {
     test -d /usr/bin || mkdir -p /usr/bin
     test -e /usr/bin/hostname || ln -s /bin/hostname /usr/bin/hostname
     mkdir /var/lib/mysql
-    chown mysql.nogroup /var/lib/mysql
+    chown mysql.mysql /var/lib/mysql
 
     mysql_install_db --basedir=${prefix} --user=mysql