Description of problem:
When virt-who run at esx mode, sometimes virt-who service can't stop/restart until over one minute

Version-Release number of selected component (if applicable):
subscription-manager-1.13.6-1.el7.x86_64
python-rhsm-1.13.6-1.el7.x86_64
virt-who-0.11-2.el7.noarch
katello-headpin-1.4.3.28-1.el6sam_splice.noarch
candlepin-0.9.6.5-1.el6sam.noarch

How reproducible:
30%

Steps to Reproduce:
1. Register system to SAM server
2. Make virt-who run at esx mode, configure as the following:
# vim /etc/sysconfig/virt-who
VIRTWHO_BACKGROUND=1
VIRTWHO_DEBUG=1
VIRTWHO_INTERVAL=5
VIRTWHO_ESX_OWNER=ACME_Corporation
VIRTWHO_ESX_ENV=Library
VIRTWHO_ESX_SERVER=10.66.79.89
VIRTWHO_ESX_USERNAME=Administrator@vsphere.local
VIRTWHO_ESX_PASSWORD=qwer1234P!
3. Restart virt-who service ,virt-who run at esx mode normally.
[root@hp-z220-06 ~]# service virt-who status
Redirecting to /bin/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)
   Active: active (running) since Fri 2014-11-07 14:29:49 CST; 8s ago
 Main PID: 6419 (python)
   CGroup: /system.slice/virt-who.service
           └─6419 /usr/bin/python /usr/share/virt-who/virtwho.py

Nov 07 14:29:49 hp-z220-06.qe.lab.eng.nay.redhat.com systemd[1]: Started Daemon for reporting virtual guest IDs to subscription-manager.
Nov 07 14:29:49 hp-z220-06.qe.lab.eng.nay.redhat.com python[6419]: Using virt-who configuration: virt-who
Nov 07 14:29:49 hp-z220-06.qe.lab.eng.nay.redhat.com python[6419]: Starting infinite loop with 5 seconds interval
Nov 07 14:29:55 hp-z220-06.qe.lab.eng.nay.redhat.com python[6419]: Sending update in hosts-to-guests mapping: {aee4ff00-8c33-11e2-99...465]}
Hint: Some lines were ellipsized, use -l to show in full.

4. Stop/restart virt-who service 
[root@hp-z220-06 ~]# service virt-who restart
Redirecting to /bin/systemctl restart  virt-who.service
[root@hp-z220-06 ~]# ps -ef|grep virt-who
root      5837     1 48 14:13 ?        00:00:28 /usr/bin/python /usr/share/virt-who/virtwho.py
root      5842  5402  0 14:13 pts/0    00:00:00 /bin/systemctl restart virt-who.service
root      5867  5583  0 14:14 pts/2    00:00:00 grep --color=auto virt-who

Actual results:
virt-who can't stop/restart until over one minute.

Expected results:
virt-who should be stop/restart normally.

Additional info:
when virt-who run at libvirtd mode, it hasn't this problem.