Description of problem:
When system is registered to sam server, virt-who will show many error message when communicate with subscription-manager

Version-Release number of selected component (if applicable):
- RHEL7.2-20150720.0-Server-x86_64 + ESX6.0 against sam
- virt-who-0.14-2.el7.noarch
- subscription-manager-1.15.6-1.el7.x86_64
- python-rhsm-1.15.3-1.el7.x86_64


How reproducible:
always

Steps to Reproduce:
1. config /etc/rhsm/rhsm.conf for sam server
rpm -ihv http://10.66.144.177/pub/candlepin-cert-consumer-samserv.redhat.com-1.0-1.noarch.rpm

2. config /etc/sysconfig/virt-who for esx mode
# grep -v  "^#" /etc/sysconfig/virt-who
VIRTWHO_BACKGROUND=1
VIRTWHO_DEBUG=1
VIRTWHO_INTERVAL=5
VIRTWHO_ESX=1
VIRTWHO_ESX_OWNER=ACME_Corporation
VIRTWHO_ESX_ENV=Library
VIRTWHO_ESX_SERVER=10.66.78.89
VIRTWHO_ESX_USERNAME=administrator
VIRTWHO_ESX_PASSWORD=qwer1234P!


3. register host to sam server
# subscription-manager register --username=admin --password=admin
The system has been registered with ID: 345908e6-d255-44bf-bedf-2317de27217f

# subscription-manager identity 
system identity: 345908e6-d255-44bf-bedf-2317de27217f
name: dhcp-128-13.nay.redhat.com
org name: ACME_Corporation
org ID: ACME_Corporation

4. restart virt-who and check status
# systemctl restart virt-who.service

# systemctl status virt-who.service 
● virt-who.service - Daemon for reporting virtual guest IDs to subscription-manager
   Loaded: loaded (/usr/lib/systemd/system/virt-who.service; disabled; vendor preset: disabled)
   Active: active (running) since Wed 2015-07-29 15:42:29 CST; 26s ago
 Main PID: 8572 (python)
   CGroup: /system.slice/virt-who.service
           ├─8572 /usr/bin/python /usr/share/virt-who/virtwho.py
           └─8577 /usr/bin/python /usr/share/virt-who/virtwho.py

Jul 29 15:42:29 dhcp-128-13.nay.redhat.com systemd[1]: Started Daemon for reporting virtual guest IDs to subscription-manager.
Jul 29 15:42:29 dhcp-128-13.nay.redhat.com systemd[1]: Starting Daemon for reporting virtual guest IDs to subscription-manager...
Jul 29 15:42:29 dhcp-128-13.nay.redhat.com python[8572]: Using configuration "env/cmdline" ("esx" mode)

5. check rhsm.log
2015-07-29 15:43:25,168 [DEBUG]  @subscriptionmanager.py:112 - Authenticating with certificate: /etc/pki/consumer/cert.pem
2015-07-29 15:43:25,199 [DEBUG]  @subscriptionmanager.py:146 - Checking if server has capability 'hypervisor_async'
2015-07-29 15:43:25,230 [ERROR]  @virtwho.py:177 - Error in communication with subscription manager:
Traceback (most recent call last):
  File "/usr/share/virt-who/virtwho.py", line 160, in send
    self._sendGuestAssociation(report)
  File "/usr/share/virt-who/virtwho.py", line 191, in _sendGuestAssociation
    report.config.type)
  File "/usr/share/virt-who/manager/subscriptionmanager/subscriptionmanager.py", line 147, in hypervisorCheckIn
    is_async = hasattr(self.connection, 'has_capability') and self.connection.has_capability('hypervisors_async')
  File "/usr/lib64/python2.7/site-packages/rhsm/connection.py", line 787, in has_capability
    self._load_manager_capabilities()
  File "/usr/lib64/python2.7/site-packages/rhsm/connection.py", line 778, in _load_manager_capabilities
    self.capabilities = self.capabilities['managerCapabilities']
KeyError: 'managerCapabilities'


Actual results:
Error in communication with subscription manager

Expected results:
It should show the right host/guest mapping info in rhsm.og, no any error exception

Additional info: