I am using Loki. Yesterday I got mysql server update and something went wrong with it, now I can't update my system nor can I install any package.

$ sudo apt upgrade Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Setting up mysql-server-5.7 (5.7.18-0ubuntu0.16.04.1) ... insserv: warning: current start runlevel(s) (empty) of script `mysql' overrides LSB defaults (2 3 4 5). insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of script `mysql' overrides LSB defaults (0 1 6). mysql_upgrade: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) while connecting to the MySQL server Upgrade process encountered error and will not continue. mysql_upgrade failed with exit status 11 dpkg: error processing package mysql-server-5.7 (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: mysql-server-5.7 E: Sub-process /usr/bin/dpkg returned an error code (1)