radosgw-admin fails due to socket conflict

The cookbook uses the same client name for running `radosgw-admin` as `radosgw` itself uses. If `radosgw` is already running, this makes the `radosgw-admin` call FAIL.

```
STDERR: warning: line 38: 'max_open_files' in section 'global' redefined
warning: line 41: 'mon_pg_warn_max_per_osd' in section 'global' redefined
warning: line 94: 'admin_socket' in section 'client' redefined
2017-07-13 23:13:02.477423 7f2d8c85f900 -1 asok(0x55b9db93d580) AdminSocketConfigObs::init: failed: AdminSocket::bind_and_listen: failed to bind the UNIX domain socket to '/var/run/ceph/ceph-client.radosgw.us-east-1-iad1.asok': (17) File exists
failed to init realm: (2) No such file or directory
---- End output of sudo radosgw-admin region set --infile /etc/ceph/us-east-1-iad1-region.json --rgw-region us-east-1-iad1 --name client.radosgw.us-east-1-iad1
----
Ran sudo radosgw-admin region set --infile /etc/ceph/us-east-1-iad1-region.json --rgw-region us-east-1-iad1 --name client.radosgw.us-east-1-iad1
returned 2
```