UpgradeSuite.TestUpgradeStepsHostMachine consistently fails on utopic

[Curtis Hovey]

Known flakey test TestUpgradeStepsHostMachine started failing consistently on 1.24. The failure starts with the build that tested commit a96dc48. Commit d4c0679 was fine.

<http://reports.vapour.ws/releases/2717/job/run-unit-tests-utopic-amd64/attempt/2301>

[LOG] 0:01.271 INFO juju.upgrade running upgrade step: move syslog config from LogDir to DataDir
[LOG] 0:01.271 DEBUG juju.upgrade Copying "/var/log/juju/ca-cert.pem" to "/tmp/check-6448954494509810920/214/var/lib/juju/ca-cert.pem"
[LOG] 0:01.273 DEBUG juju.apiserver -> [98] machine-0 135.074017ms {"RequestId":11,"Response":"'body redacted'"} Reboot[""].WatchForRebootEvent
[LOG] 0:01.276 DEBUG juju.apiserver -> [98] machine-0 136.352897ms {"RequestId":14,"Response":"'body redacted'"} Environment[""].EnvironConfig
[LOG] 0:01.276 DEBUG juju.apiserver -> [98] machine-0 138.045753ms {"RequestId":13,"Response":"'body redacted'"} Logger[""].LoggingConfig
[LOG] 0:01.276 DEBUG juju.upgrade Copying "/var/log/juju/rsyslog-cert.pem" to "/tmp/check-6448954494509810920/214/var/lib/juju/rsyslog-cert.pem"
[LOG] 0:01.276 DEBUG juju.upgrade Old file "/var/log/juju/rsyslog-cert.pem" does not exist, skipping.
[LOG] 0:01.276 DEBUG juju.upgrade Copying "/var/log/juju/rsyslog-key.pem" to "/tmp/check-6448954494509810920/214/var/lib/juju/rsyslog-key.pem"
[LOG] 0:01.276 DEBUG juju.upgrade Old file "/var/log/juju/rsyslog-key.pem" does not exist, skipping.
[LOG] 0:01.276 DEBUG juju.upgrade Copying "/var/log/juju/logrotate.conf" to "/tmp/check-6448954494509810920/214/var/lib/juju/logrotate.conf"
[LOG] 0:01.276 DEBUG juju.upgrade Old file "/var/log/juju/logrotate.conf" does not exist, skipping.
[LOG] 0:01.276 DEBUG juju.upgrade Copying "/var/log/juju/logrotate.run" to "/tmp/check-6448954494509810920/214/var/lib/juju/logrotate.run"
[LOG] 0:01.276 DEBUG juju.upgrade Old file "/var/log/juju/logrotate.run" does not exist, skipping.
[LOG] 0:01.276 ERROR juju.upgrade upgrade step "move syslog config from LogDir to DataDir" failed: error(s) while moving old syslog config files: remove /var/log/juju/ca-cert.pem: permission denied
[LOG] 0:01.276 ERROR juju.cmd.jujud upgrade from 1.16-beta6 to 1.24-beta6 for "machine-1" failed (will retry): move syslog config from LogDir to DataDir: error(s) while moving old syslog config files: remove /var/log/juju/ca-cert.pem: permission denied

Change that added the broken upgrade step:

<https://github.com/juju/juju/pull/2458>