Security-related updates to MySQL delivered in MOS8 MU4 cannot be installed

[Anatolii Neliubin]

Security-related update to MySQL is not installed during installation of MU4 for MOS8. According to https://docs.mirantis.com/openstack/fuel/fuel-8.0/maintenance-updates.html#mu8-0-4-security. version of MySQL is to be updated to 5.6.35; however, standard way of installing this fix from https://docs.mirantis.com/openstack/fuel/fuel-8.0/maintenance-updates.html#mu8-0-how-to-update does not work properly:
root@node-3:~# #BEFORE UPGRADE
root@node-3:~# dpkg -l | grep mysql
ii libdbd-mysql-perl 4.025-1 amd64 Perl5 database interface to the MySQL database
ii libmysqlclient18:amd64 5.5.47-0ubuntu0.14.04.1 amd64 MySQL database client library
ii mysql-client-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database client binaries
ii mysql-client-core-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database core client binaries
ii mysql-common 5.5.47-0ubuntu0.14.04.1 all MySQL database common files, e.g. /etc/mysql/my.cnf
ii mysql-server-wsrep-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database server binaries and system database setup
ii mysql-server-wsrep-core-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database server binaries
ii mysql-wsrep-common-5.6 5.6.23-1~u14.04+mos1 all MySQL 5.6 specific common files, e.g. /etc/mysql/conf.d/my-5.6.cnf
ii python-mysqldb 1.3.4-2~u14.04+mos1 amd64 Python interface to MySQL
ii python-pymysql 0.6.7-1~u14.04+mos1 all Pure-Python MySQL driver - Python 2.7
root@node-3:~# #AFTER UPGRADE
root@node-3:~# dpkg -l | grep mysql
ii libdbd-mysql-perl 4.025-1 amd64 Perl5 database interface to the MySQL database
ii libmysqlclient18:amd64 5.5.47-0ubuntu0.14.04.1 amd64 MySQL database client library
ii mysql-client-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database client binaries
ii mysql-client-core-5.6 5.6.30-0~u14.04+mos1 amd64 MySQL database core client binaries
ii mysql-common 5.5.47-0ubuntu0.14.04.1 all MySQL database common files, e.g. /etc/mysql/my.cnf
ii mysql-server-wsrep-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database server binaries and system database setup
ii mysql-server-wsrep-core-5.6 5.6.23-1~u14.04+mos1 amd64 MySQL database server binaries
ii mysql-wsrep-common-5.6 5.6.35-0~u14.04+mos2 all MySQL database common files, e.g. /etc/mysql/conf.d/my-5.6.cnf
ii python-mysqldb 1.3.4-2~u14.04+mos1 amd64 Python interface to MySQL
ii python-pymysql 0.6.7-1~u14.04+mos1 all Pure-Python MySQL driver - Python 2.7
root@node-3:~#
root@node-3:~# apt-get -o Dir::etc::sourcelist=- -o Dir::Etc::sourceparts=/root/mos_update_repo/ -o APT::Get::List-Cleanup=0 -o Dpkg::Options::=--force-confdef -o Dpkg::Options::=--force-confold -y --force-yes upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
  cloud-guest-utils eatmydata python-oauth python-serial python3-pycurl
  python3-software-properties software-properties-common unattended-upgrades
Use 'apt-get autoremove' to remove them.
The following packages have been kept back:
  keepalived libmysqlclient18 mysql-client-5.6 mysql-server-wsrep-5.6
  mysql-server-wsrep-core-5.6
0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.
root@node-3:~#