package libmysqlclient18 5.5.38-0ubuntu0.14.04.1 failed to install/upgrade: libmysqlclient18:amd64 10.0.13+maria-1~trusty (Multi-Arch: no) is not co-installable with libmysqlclient18 which has multiple installed instances

[Matt Chapman]

Following attempted cross-grade to MariaDB, and then removing Maria packages and restoring mysql.

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: libmysqlclient18 5.5.38-0ubuntu0.14.04.1
ProcVersionSignature: Ubuntu 3.13.0-35.62-generic 3.13.11.6
Uname: Linux 3.13.0-35-generic x86_64
.etc.apparmor.d.usr.sbin.mysqld: # vim:syntax=apparmor
ApportVersion: 2.14.1-0ubuntu3.4
Architecture: amd64
Date: Sun Sep 14 10:31:59 2014
DpkgTerminalLog:
 Preparing to unpack .../libmariadbclient18_10.0.13+maria-1~trusty_amd64.deb ...
 Unpacking libmariadbclient18 (10.0.13+maria-1~trusty) ...
 dpkg: error processing archive /var/cache/apt/archives/libmysqlclient18_10.0.13+maria-1~trusty_amd64.deb (--unpack):
  libmysqlclient18:amd64 10.0.13+maria-1~trusty (Multi-Arch: no) is not co-installable with libmysqlclient18 which has multiple installed instances
DuplicateSignature: package:libmysqlclient18:5.5.38-0ubuntu0.14.04.1:libmysqlclient18:amd64 10.0.13+maria-1~trusty (Multi-Arch: no) is not co-installable with libmysqlclient18 which has multiple installed instances
ErrorMessage: libmysqlclient18:amd64 10.0.13+maria-1~trusty (Multi-Arch: no) is not co-installable with libmysqlclient18 which has multiple installed instances
InstallationDate: Installed on 2014-05-05 (137 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
Logs.var.log.daemon.log:

MySQLConf.etc.mysql.conf.d..keepme:
MySQLConf.etc.mysql.conf.d.mysqld.safe.syslog.cnf:
 [mysqld_safe]
 syslog
MySQLVarLibDirListing: ['mysql@002dbak', 'mysql_upgrade_info', 'drupal7', 'ib_logfile0', 'matt-Lenovo-Ubuntu.log', 'ib_logfile0.bak', 'ib_logfile1', 'cardlike', 'ibdata1.bak', 'ibdata1', 'debian-5.5.flag', 'cardcom', 'mysql', 'ib_logfile1.bak', 'phpmyadmin', 'performance_schema']
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-3.13.0-35-generic.efi.signed root=UUID=e55fd7ff-3130-4675-9cd8-e7739e4aa8c1 ro quiet splash vt.handoff=7
SourcePackage: mysql-5.5
Title: package libmysqlclient18 5.5.38-0ubuntu0.14.04.1 failed to install/upgrade: libmysqlclient18:amd64 10.0.13+maria-1~trusty (Multi-Arch: no) is not co-installable with libmysqlclient18 which has multiple installed instances
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.apparmor.d.usr.sbin.mysqld: [modified]
mtime.conffile..etc.apparmor.d.usr.sbin.mysqld: 2014-09-14T11:38:15.685764