Description of problem:
if I set VIRTWHO_ONE_SHOT=1 in /etc/sysconfig/virt-who for one shot, virt-who will not exit immediately

Version-Release number of selected component (if applicable):
virt-who-0.16-1.el6.noarch

How reproducible:
always

Steps to Reproduce:
1. set VIRTWHO_ONE_SHOT=1 in /etc/sysconfig/virt-who
VIRTWHO_DEBUG=1
VIRTWHO_ONE_SHOT=1
VIRTWHO_LIBVIRT=1
VIRTWHO_LIBVIRT_OWNER=ACME_Corporation
VIRTWHO_LIBVIRT_ENV=Library
VIRTWHO_LIBVIRT_SERVER=10.66.144.8
VIRTWHO_LIBVIRT_USERNAME=root
VIRTWHO_LIBVIRT_PASSWORD=redhat


2. restart virt-who service and check the rhsm.log
# /etc/init.d/virt-who restart
# tail -f /var/log/rhsm/rhsm.log
2015-12-30 15:06:29,652 [virtwho.main DEBUG] MainProcess(23172):MainThread @subscriptionmanager.py:hypervisorCheckIn:171 - Host-to-guest mapping: {
    "80804c56-82fb-e111-a260-b4b52fcb471e": [
        {
            "guestId": "cb33ddce-fd1e-0e6a-7e7f-d3c6fca67ede", 
            "state": 1, 
            "attributes": {
                "active": 1, 
                "hypervisorVersion": "0.12.1", 
                "virtWhoType": "libvirt", 
                "hypervisorType": "QEMU"
            }
        }
    ]
}
2015-12-30 15:06:29,960 [virtwho.main DEBUG] MainProcess(23172):MainThread @virtwho.py:send_current_report:206 - Report for config "env/cmdline" sent


3. check the virt-who service
# ps -ef|grep virtwho
root     23172     1  0 15:06 ?        00:00:00 /usr/bin/python /usr/share/virt-who/virtwho.py
root     23180 23172  0 15:06 ?        00:00:00 /usr/bin/python /usr/share/virt-who/virtwho.py

===> virt-who will not exit 

4. pause or poweroff guest, and check the rhsm.log
2015-12-30 15:10:30,107 [virtwho.main DEBUG] MainProcess(23172):MainThread @subscriptionmanager.py:hypervisorCheckIn:171 - Host-to-guest mapping: {
    "80804c56-82fb-e111-a260-b4b52fcb471e": [
        {
            "guestId": "cb33ddce-fd1e-0e6a-7e7f-d3c6fca67ede", 
            "state": 3, 
            "attributes": {
                "active": 1, 
                "hypervisorVersion": "0.12.1", 
                "virtWhoType": "libvirt", 
                "hypervisorType": "QEMU"
            }
        }
    ]
}
2015-12-30 15:10:30,397 [virtwho.main DEBUG] MainProcess(23172):MainThread @virtwho.py:send_current_report:206 - Report for config "env/cmdline" sent

===> virt-who still can send the json info for update


Actual results:
VIRTWHO_ONE_SHOT=1 is invalid in /etc/sysconfig/virt-who, still can send the updated json info

Expected results:
if set VIRTWHO_ONE_SHOT=1 in /etc/sysconfig/virt-who, virt-who should be run one shot

Additional info: