Description of problem:
When virt-who interval is small(eg: VIRTWHO_INTERVAL=5), it's very easy lead to  virt-who failed to communication with subscription manager,please see bug 1105053 and bug 1216278 

Version-Release number of selected component (if applicable):
virt-who-0.12-7.el6.noarch
subscription-manager-1.14.6-1.el6.x86_64
python-rhsm-1.14.2-1.el6.x86_64
candlepin-0.9.49.0-1.el7.noarch
katello-2.2.0.8-1.el7sat.noarch
foreman-1.7.2.19-1.el7sat.noarch
Satellite-6.1.0-RHEL-7-20150506.0

How reproducible:
Always

Steps to Reproduce:
1. Register system to Satellite/SAM
2. Configure virt-who interval to 5 then restart virt-who service
# vim /etc/sysconfig/virt-who
VIRTWHO_BACKGROUND=1
VIRTWHO_DEBUG=1
VIRTWHO_INTERVAL=5
# service virt-who restart
3.Unregister system
# subscription-manager unregister
# tail -f /var/log/rhsm/rhsm.log
2015-05-11 17:07:08,882 [ERROR]  @virtwho.py:115 - Error in communication with subscription manager:
Traceback (most recent call last):
  File "/usr/share/virt-who/virtwho.py", line 102, in send
    self._sendGuestList(report)
  File "/usr/share/virt-who/virtwho.py", line 121, in _sendGuestList
    manager.sendVirtGuests(report.guests)
  File "/usr/share/virt-who/manager/subscriptionmanager/subscriptionmanager.py", line 119, in sendVirtGuests
    self.connection.updateConsumer(self.uuid(), guest_uuids=domains)
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 858, in updateConsumer
    ret = self.conn.request_put(method, params)
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 611, in request_put
    return self._request("PUT", method, params)
  File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 505, in _request
    conn.request(request_type, handler, body=body, headers=headers)
  File "/usr/lib64/python2.6/httplib.py", line 936, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib64/python2.6/httplib.py", line 973, in _send_request
    self.endheaders()
  File "/usr/lib64/python2.6/httplib.py", line 930, in endheaders
    self._send_output()
  File "/usr/lib64/python2.6/httplib.py", line 802, in _send_output
    self.send(msg)
  File "/usr/lib64/python2.6/httplib.py", line 761, in send
    self.connect()
  File "/usr/lib64/python2.6/site-packages/M2Crypto/httpslib.py", line 73, in connect
    raise error
error: [Errno 4] Interrupted system call

Actual results:
When the refresh interval is too small, It will show many error messages when virt-who communication with subscription manager

Expected results:
If virt-who can limit the interval to at least 1 minute, it won't generate these errors 

Additional info: