Description of problem:
If there was a hostname exist on server, virt-who send the same hostname to server again, although it won't generate two same hostnames in server any more, virt-who will updated the previous host's uuid and it result in virt-who can't send mapping info to server.

Version-Release number of selected component (if applicable):
virt-who-0.17-7.el7.noarch
subscription-manager-1.17.9-1.el7.x86_64
python-rhsm-1.17.5-1.el7.x86_64

How reproducible:
Always

Steps to Reproduce:
Precondition:
Virt-who work at a RHEL host and this host has been added to rhevm

Process:
1. Register RHEL Host to satellite6.2, the registed host's uuid is "38ceb55a-e12d-443d-8f42-e62be5d75010", please see screenshot in attachment old_uuid.jpeg
[root@hp-dl560egen8-01 virt-who.d]# subscription-manager  register --username=admin --password=admin
Registering to: hp-dl2x170g6-01.rhts.eng.bos.redhat.com:443/rhsm
The system has been registered with ID: 38ceb55a-e12d-443d-8f42-e62be5d75010 

2. Configure virt-who work at rhevm mode and report hostname instead of hostuuid
[root@hp-dl560egen8-01 virt-who.d]# cat /etc/virt-who.d/rhevm 
[test-rhevm1]
type=rhevm
server=https://ibm-x3690x5-01.rhts.eng.bos.redhat.com:443/ovirt-engine/
username=admin@internal
encrypted_password=48aeec0241dc902f383f94f32efc2fb3
owner=ACME_Corporation
env=Library
hypervisor_id=hostname

3. Restart virt-who and check virt-who's log, virt-who send host/guest mapping info to satellite sucessfully and virt-who updated the host's uuid to "983d6840-e219-4521-9a11-fce9ba1e8f68". see screenshot in attachment updated_uuid.jpeg
[root@hp-dl560egen8-01 ~]# tail -f /var/log/rhsm/rhsm.log
2016-08-02 04:35:38,958 [virtwho.init DEBUG] MainProcess(3990):MainThread @executor.py:__init__:65 - Using config named 'test-rhevm1'
2016-08-02 04:35:38,959 [virtwho.init INFO] MainProcess(3990):MainThread @main.py:main:160 - Using configuration "test-rhevm1" ("rhevm" mode)
2016-08-02 04:35:38,959 [virtwho.init INFO] MainProcess(3990):MainThread @main.py:main:162 - Using reporter_id='hp-dl560egen8-01.khw.lab.eng.bos.redhat.com-802e3ee1794e4d728db29e3f9fbae108'
2016-08-02 04:35:38,962 [virtwho.main DEBUG] MainProcess(3990):MainThread @executor.py:run:171 - Starting infinite loop with 60 seconds interval
2016-08-02 04:35:39,006 [virtwho.test-rhevm1 DEBUG] RhevM-1(3997):MainThread @virt.py:run:364 - Virt backend 'test-rhevm1' started
2016-08-02 04:35:39,540 [virtwho.test-rhevm1 DEBUG] RhevM-1(3997):MainThread @virt.py:enqueue:357 - Report for config "test-rhevm1" gathered, putting to queue for sending
2016-08-02 04:35:39,555 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:_connect:123 - Authenticating with certificate: /etc/pki/consumer/cert.pem
2016-08-02 04:35:39,915 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:171 - Checking if server has capability 'hypervisor_async'
2016-08-02 04:35:40,231 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:183 - Server does not have 'hypervisors_async' capability
2016-08-02 04:35:40,231 [virtwho.main INFO] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:194 - Sending update in hosts-to-guests mapping for config "test-rhevm1": 2 hypervisors and 1 guests found
2016-08-02 04:35:40,231 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:195 - Host-to-guest mapping: {
    "hp-dl560egen8-01.khw.lab.eng.bos.redhat.com": [
        {
            "guestId": "530c34dc-2086-4f1d-a509-c417950bd0cb", 
            "state": 1, 
            "attributes": {
                "active": 1, 
                "virtWhoType": "rhevm"
            }
        }
    ], 
    "dell-pe1950-06.rhts.englab.brq.redhat.com": []
}
2016-08-02 04:35:42,761 [virtwho.main DEBUG] MainProcess(3990):MainThread @executor.py:send_report:101 - Report for config "test-rhevm1" sent


4. In rhevm webUI, update host or guest's info, eg: add a guest, wait for 60s, check virt-who's log
[root@hp-dl560egen8-01 ~]# tail -f /var/log/rhsm/rhsm.log
2016-08-02 04:37:40,711 [virtwho.test-rhevm1 DEBUG] RhevM-1(3997):MainThread @virt.py:enqueue:357 - Report for config "test-rhevm1" gathered, putting to queue for sending
2016-08-02 04:37:40,715 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:_connect:123 - Authenticating with certificate: /etc/pki/consumer/cert.pem
2016-08-02 04:37:41,168 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:171 - Checking if server has capability 'hypervisor_async'
2016-08-02 04:37:41,476 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:183 - Server does not have 'hypervisors_async' capability
2016-08-02 04:37:41,476 [virtwho.main INFO] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:194 - Sending update in hosts-to-guests mapping for config "test-rhevm1": 2 hypervisors and 2 guests found
2016-08-02 04:37:41,476 [virtwho.main DEBUG] MainProcess(3990):MainThread @subscriptionmanager.py:hypervisorCheckIn:195 - Host-to-guest mapping: {
    "hp-dl560egen8-01.khw.lab.eng.bos.redhat.com": [
        {
            "guestId": "530c34dc-2086-4f1d-a509-c417950bd0cb", 
            "state": 1, 
            "attributes": {
                "active": 1, 
                "virtWhoType": "rhevm"
            }
        }
    ], 
    "dell-pe1950-06.rhts.englab.brq.redhat.com": [
        {
            "guestId": "4c4f9cbd-d811-4061-9aeb-050b774b870a", 
            "state": 5, 
            "attributes": {
                "active": 0, 
                "virtWhoType": "rhevm"
            }
        }
    ]
}
2016-08-02 04:37:41,718 [virtwho.main ERROR] MainProcess(3990):MainThread @executor.py:send:143 - Unable to send data: Communication with subscription manager failed with code 404: Couldn't find consumer '38ceb55a-e12d-443d-8f42-e62be5d75010'
2016-08-02 04:37:41,718 [virtwho.main DEBUG] MainProcess(3990):MainThread @executor.py:send_report:108 - Report from "test-rhevm1" failed to sent

5. Check host's registered status.
[root@hp-dl560egen8-01 virt-who.d]# subscription-manager  identity
system identity: 38ceb55a-e12d-443d-8f42-e62be5d75010
name: hp-dl560egen8-01.khw.lab.eng.bos.redhat.com
org name: Default Organization
org ID: Default_Organization
Couldn't find consumer '38ceb55a-e12d-443d-8f42-e62be5d75010'

Actual results:
Failed to send update info to server since the old host's uuid(38ceb55a-e12d-443d-8f42-e62be5d75010) has been updated by virt-who.
Unable to send data: Communication with subscription manager failed with code 404: Couldn't find consumer '38ceb55a-e12d-443d-8f42-e62be5d75010'

Expected results:
Virt-who should send update info to server successfully 

Additional info: