Description of problem:
Unregistered system, it will appear error message "Error while checking server version: 'rulesVersion'" in the virt-who log.both "rules-version" and "candlepin version" are 'Unknown'

Version-Release number of selected component (if applicable):
subscription-manager-1.12.4-1.el6.x86_64
python-rhsm-1.12.4-1.el6.x86_64
virt-who-0.10-3.el6.noarch
katello-headpin-1.4.3.26-1.el6sam_splice.noarch
candlepin-0.9.6.4-1.el6sam.noarch

How reproducible:
Always

Steps to Reproduce:
1.Register system to SAM server
# subscription-manager register --username=admin --password=admin
2. Configure virt-who run at libvirtd mode
# vim /etc/sysconfig/virt-who
VIRTWHO_BACKGROUND=1
VIRTWHO_DEBUG=1
VIRTWHO_INTERVAL=5
3. Restart virt-who service, virt-who send host/guest associate to SAM server
# service virt-who restart
4. Unregister the system
#  subscription-manager unregister

Actual results:
System has been unregistered successfully, but it will generate error message "Error while checking server version: 'rulesVersion'" in the virt-who log, it failed to get value of "rules-version" and "candlepin version". both of them are "Unknown". please see detail as the following:

subscription-manager @plugins.py:569 - loaded plugin modules: []
2014-07-30 13:08:21,522 [DEBUG] subscription-manager @plugins.py:570 - loaded plugins: {}
2014-07-30 13:08:21,522 [DEBUG] subscription-manager @identity.py:131 - Loading consumer info from identity certificates.
2014-07-30 13:08:21,550 [DEBUG] subscription-manager @profile.py:97 - Loading current RPM profile.
2014-07-30 13:08:21,639 [INFO] subscription-manager @managercli.py:298 - Client Versions: {'python-rhsm': '1.12.4-1.el6', 'subscription-manager': '1.12.4-1.el6'}
2014-07-30 13:08:21,640 [INFO] subscription-manager @connection.py:659 - Using certificate authentication: key = /etc/pki/consumer/key.pem, cert = /etc/pki/consumer/cert.pem, ca = /etc/rhsm/ca/, insecure = False
2014-07-30 13:08:21,640 [INFO] subscription-manager @connection.py:670 - Connection Built: host: samserv.redhat.com, port: 443, handler: /sam/api
2014-07-30 13:08:21,640 [INFO] subscription-manager @connection.py:666 - Using no auth
2014-07-30 13:08:21,640 [INFO] subscription-manager @connection.py:670 - Connection Built: host: samserv.redhat.com, port: 443, handler: /sam/api
2014-07-30 13:08:21,651 [DEBUG] subscription-manager @connection.py:414 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-local.pem, candlepin-stage.pem
2014-07-30 13:08:21,651 [DEBUG] subscription-manager @connection.py:446 - Making request: GET /sam/api/
2014-07-30 13:08:21,700 [DEBUG] subscription-manager @connection.py:469 - Response: status=200
2014-07-30 13:08:21,702 [DEBUG] subscription-manager @connection.py:686 - Server supports the following resources:
2014-07-30 13:08:21,703 [DEBUG] subscription-manager @connection.py:687 - {'status': '/api/status/', 'organizations': '/api/organizations/', 'roles': '/api/roles/', 'sync_plans': '/api/sync_plans/', 'users': '/api/users/', 'distributors': '/api/distributors/', 'providers': '/api/providers/', 'entitlements': '/api/entitlements/', 'content_overrides': '/api/content_overrides', 'content_views': '/api/content_views/', 'guestids': '/api/guestids', 'system_groups': '/api/system_groups/', 'products': '/api/products/', 'systems': '/api/systems/', 'activation_keys': '/api/activation_keys/', 'content_view_definitions': '/api/content_view_definitions/', 'consumers': '/api/consumers/'}
2014-07-30 13:08:21,704 [DEBUG] subscription-manager @connection.py:414 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-local.pem, candlepin-stage.pem
===================================================
2014-07-30 13:08:21,704 [DEBUG] subscription-manager @connection.py:446 - Making request: GET /sam/api/status
2014-07-30 13:08:21,732 [DEBUG] subscription-manager @connection.py:469 - Response: status=200
2014-07-30 13:08:21,733 [ERROR] subscription-manager @utils.py:240 - Error while checking server version: 'rulesVersion'
2014-07-30 13:08:21,733 [ERROR] subscription-manager @utils.py:242 - 'rulesVersion'
Traceback (most recent call last):
  File "/usr/share/rhsm/subscription_manager/utils.py", line 224, in get_server_versions
    rules_version = status['rulesVersion']
KeyError: 'rulesVersion'
2014-07-30 13:08:21,734 [INFO] subscription-manager @managercli.py:309 - Server Versions: {'rules-version': 'Unknown', 'candlepin': 'Unknown', 'server-type': 'Red Hat Subscription Management'}
===================================================
2014-07-30 13:08:21,734 [INFO] subscription-manager @managercli.py:274 - self.identity: <Identity, name=hp-z220-05.qe.lab.eng.nay.redhat.com, uuid=51d50263-816c-4caa-9511-5bb56d6c8f1a, consumer=consumer: name="hp-z220-05.qe.lab.eng.nay.redhat.com", uuid=51d50263-816c-4caa-9511-5bb56d6c8f1a>
2014-07-30 13:08:21,736 [DEBUG] subscription-manager @connection.py:414 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-local.pem, candlepin-stage.pem
2014-07-30 13:08:21,737 [DEBUG] subscription-manager @connection.py:446 - Making request: DELETE /sam/api/consumers/51d50263-816c-4caa-9511-5bb56d6c8f1a
2014-07-30 13:08:22,255 [DEBUG] subscription-manager @connection.py:469 - Response: status=204
2014-07-30 13:08:22,256 [INFO] subscription-manager @managerlib.py:802 - Successfully un-registered.
2014-07-30 13:08:22,263 [DEBUG] subscription-manager @managerlib.py:848 - Removing identity cert: /etc/pki/consumer/key.pem
2014-07-30 13:08:22,263 [DEBUG] subscription-manager @managerlib.py:848 - Removing identity cert: /etc/pki/consumer/cert.pem
2014-07-30 13:08:22,263 [DEBUG] subscription-manager @identity.py:131 - Loading consumer info from identity certificates.


Expected results:
system unregistered successfully, and it won't generate any error message when check "rules-version" and "candlepin", it should display the correct value of "rules-version" and "candlepin version",just the same as RHEL5.11. Please see the correct virt-who log on RHEL5.11

2014-07-30 01:09:58,294 [DEBUG] subscription-manager @plugins.py:533 - loaded plugin modules: []
2014-07-30 01:09:58,294 [DEBUG] subscription-manager @plugins.py:534 - loaded plugins: {}
2014-07-30 01:09:58,320 [DEBUG] subscription-manager @identity.py:131 - Loading consumer info from identity certificates.
2014-07-30 01:09:58,327 [DEBUG] subscription-manager @profile.py:97 - Loading current RPM profile.
2014-07-30 01:09:58,414 [INFO] subscription-manager @managercli.py:293 - Client Versions: {'python-rhsm': '1.11.3-5.el5', 'subscription-manager': '1.11.3-10.el5'}
2014-07-30 01:09:58,415 [INFO] subscription-manager @connection.py:661 - Using certificate authentication: key = /etc/pki/consumer/key.pem, cert = /etc/pki/consumer/cert.pem, ca = /etc/rhsm/ca/, insecure = False
2014-07-30 01:09:58,415 [INFO] subscription-manager @connection.py:674 - Connection Built: host: samserv.redhat.com, port: 443, handler: /sam/api
2014-07-30 01:09:58,415 [INFO] subscription-manager @connection.py:671 - Using no auth
2014-07-30 01:09:58,415 [INFO] subscription-manager @connection.py:674 - Connection Built: host: samserv.redhat.com, port: 443, handler: /sam/api
2014-07-30 01:09:58,429 [DEBUG] subscription-manager @connection.py:419 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-stage.pem, candlepin-local.pem
2014-07-30 01:09:58,429 [DEBUG] subscription-manager @connection.py:451 - Making request: GET /sam/api/
2014-07-30 01:09:58,477 [DEBUG] subscription-manager @connection.py:474 - Response: status=200
2014-07-30 01:09:58,478 [DEBUG] subscription-manager @connection.py:691 - Server supports the following resources:
2014-07-30 01:09:58,479 [DEBUG] subscription-manager @connection.py:692 - {'status': '/api/status/', 'organizations': '/api/organizations/', 'roles': '/api/roles/', 'sync_plans': '/api/sync_plans/', 'users': '/api/users/', 'distributors': '/api/distributors/', 'providers': '/api/providers/', 'entitlements': '/api/entitlements/', 'content_overrides': '/api/content_overrides', 'content_views': '/api/content_views/', 'guestids': '/api/guestids', 'system_groups': '/api/system_groups/', 'products': '/api/products/', 'systems': '/api/systems/', 'activation_keys': '/api/activation_keys/', 'content_view_definitions': '/api/content_view_definitions/', 'consumers': '/api/consumers/'}
2014-07-30 01:09:58,480 [DEBUG] subscription-manager @connection.py:419 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-stage.pem, candlepin-local.pem
===================================================
2014-07-30 01:09:58,480 [DEBUG] subscription-manager @connection.py:451 - Making request: GET /sam/api/status
2014-07-30 01:09:58,510 [DEBUG] subscription-manager @connection.py:474 - Response: status=200
2014-07-30 01:09:58,510 [INFO] subscription-manager @managercli.py:304 - Server Versions: {'candlepin': '1.4.3.26-1.el6sam_splice-Headpin', 'server-type': 'Red Hat Subscription Management'}
===================================================
2014-07-30 01:09:58,514 [DEBUG] subscription-manager @connection.py:419 - Loaded CA certificates from /etc/rhsm/ca/: redhat-uep.pem, candlepin-stage.pem, candlepin-local.pem
2014-07-30 01:09:58,514 [DEBUG] subscription-manager @connection.py:451 - Making request: DELETE /sam/api/consumers/50ea400d-0cbd-4669-b80e-d0ac9588b6a6
2014-07-30 01:09:58,825 [DEBUG] subscription-manager @connection.py:474 - Response: status=204
2014-07-30 01:09:58,826 [INFO] subscription-manager @managerlib.py:800 - Successfully un-registered.


Additional info: