This patchset implements key rotation in the ceph-radosgw charm,
by replacing the keyring file if it exists and the ceph-mon
relation reports a new key.
Update tox.ini to support the new TEST_CONSTRAINTS_FILE
Additionally pin netaddr in test-requirements.txt. The latest netaddr
1.2.1 release throws an error when passed None, which it previously
didn't. This causes MonContextTest.test_ctxt_missing_data to error out.
This should probably be fixed in charmhelpers later.
The Openstack libs don't recognize Ceph releases when specifying
the charm source. Instead, we have to use an Openstack release.
Since it was set to quincy, reset it to bobcat.
Patch out charmhelpers.osplatform.get_platform() and
charmhelpers.core.host.lsb_release() globally in the unit tests to
insulate the unit tests from the platform that the unit tests are being
run on.
Also, add mock for `charmhelpers.contrib.openstack.context.is_ipv6_disabled`
in the `HAProxyContextTests.test_ctxt` unit test.
The charmhelpers function `is_ipv6_disabled` calls `sysctl` and this doesn't
exist on Debian container images. This fixes the following unit test failure:
```
FileNotFoundError: [Errno 2] No such file or directory: 'sysctl'
```