Description of problem:
After removed subscribed pool, it can't add the removed pools to available list.

Version-Release number of selected component (if applicable):
Satellite-6.2.0-RHEL-7-20160518
virt-who-0.17-1.el7.noarch
subscription-manager-1.17.6-1.el7.x86_64
python-rhsm-1.17.2-1.el7.x86_64

How reproducible:


Steps to Reproduce:
1. Register host to satellite
2. Open satellite webUI, subscribe and check available pool of "Red Hat Enterprise Linux Server, Premium (Physical or Virtual Nodes)"as the following:

go to Hosts-->Content hosts, click on host, jump to host detail page, go to Subscriptions-->Add, it will show the available pool quantity of "Red Hat Enterprise Linux Server, Premium (Physical or Virtual Nodes)" under "Attach" tab  is "0 out of 50"(see attachment "before attach"), click on "Add Selected", it will subscribe two pools.

3. In webUI, check the quantity of available pool of "Red Hat Enterprise Linux Server, Premium (Physical or Virtual Nodes)" is "2 out of 50"(see attachment "after attach")
4. In webUI, Remove the subscribed pool on step2
5. Check the quantity of available pool of "Red Hat Enterprise Linux Server, Premium (Physical or Virtual Nodes)"

Actual results:
It still show "2 out of 50"(see attachment "after remove")

Expected results:
It should show "0 out of 50" since it hasn't been subscribed by any host.

Additional info: