Comment 0 for bug 1561087

Hit this traceback with cs:~openstack-charmers-next/trusty/swift-proxy-43:

2016-03-23 06:36:11 INFO swift-storage-relation-changed E: Problem renaming the file /var/
cache/apt/pkgcache.bin.CWnMSY to /var/cache/apt/pkgcache.bin - rename (2: No such file or
directory)
2016-03-23 06:36:11 INFO swift-storage-relation-changed W: You may want to run apt-get upd
ate to correct these problems
2016-03-23 06:36:11 INFO swift-storage-relation-changed Traceback (most recent call last):
2016-03-23 06:36:11 INFO swift-storage-relation-changed File "/var/lib/juju/agents/unit-swift-proxy-0/charm/hooks/swift-storage-relation-changed", line 97, in <module>
2016-03-23 06:36:11 INFO swift-storage-relation-changed CONFIGS = register_configs()
2016-03-23 06:36:11 INFO swift-storage-relation-changed File "/var/lib/juju/agents/unit-swift-proxy-0/charm/hooks/lib/swift_utils.py", line 296, in register_configs
2016-03-23 06:36:11 INFO swift-storage-relation-changed release = get_os_codename_package('swift-proxy', fatal=False) \
2016-03-23 06:36:11 INFO swift-storage-relation-changed File "/var/lib/juju/agents/unit-swift-proxy-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 303, in get_os_codename_package
2016-03-23 06:36:11 INFO swift-storage-relation-changed return get_swift_codename(vers)
2016-03-23 06:36:11 INFO swift-storage-relation-changed File "/var/lib/juju/agents/unit-swift-proxy-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 252, in get_swift_codename
2016-03-23 06:36:11 INFO swift-storage-relation-changed ret = subprocess.check_output(['apt-cache', 'policy', 'swift'])
2016-03-23 06:36:11 INFO swift-storage-relation-changed File "/usr/lib/python2.7/subprocess.py", line 573, in check_output
2016-03-23 06:36:11 INFO swift-storage-relation-changed raise CalledProcessError(retcode, cmd, output=output)
de, cmd, output=output)
2016-03-23 06:36:11 INFO swift-storage-relation-changed subprocess.CalledProcessError: Command '['apt-cache', 'policy', 'swift']' returned non-zero exit status 100
2016-03-23 06:36:11 ERROR juju.worker.uniter.operation runhook.go:107 hook "swift-storage-relation-changed" failed: exit status 1

This appears to be another case of https://bugs.launchpad.net/charms/+source/ceph-radosgw/+bug/1346489, but for the swift-proxy charm.

An examination of logs shows apt-get update events occurring at the same time as this failure within other units on the same instance.