package mysql-server-5.7 5.7.18-0ubuntu0.16.04.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

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ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mysql-server-5.7 5.7.18-0ubuntu0.16.04.1
ProcVersionSignature: Ubuntu 4.8.0-49.52~16.04.1-generic 4.8.17
Uname: Linux 4.8.0-49-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
Date: Tue May 2 10:13:12 2017
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2017-04-06 (25 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
Logs.var.log.daemon.log:

Logs.var.log.mysql.error.log:
MySQLVarLibDirListing: ['ib_buffer_pool', 'auto.cnf', 'ib_logfile1', 'ibdata1', 'debian-5.7.flag', 'mysql', 'ib_logfile0', 'performance_schema', 'mysql_upgrade_info', 'sys']
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-4.8.0-49-generic root=UUID=c4ef52d5-e088-400a-9418-2fa03102fa0a ro quiet splash security=selinux selinux=1 vt.handoff=7
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.19
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.18-0ubuntu0.16.04.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.mysql.debian-start: [deleted]
modified.conffile..etc.mysql.mysql.cnf: [modified]
modified.conffile..etc.mysql.mysql.conf.d.mysqld.cnf: [deleted]
modified.conffile..etc.mysql.mysql.conf.d.mysqld_safe_syslog.cnf: [deleted]
mtime.conffile..etc.mysql.mysql.cnf: 2017-04-14T13:47:35.766336