Description of problem:
Storage/Memory/Terminating add on can be downgrade to 0 enenthough user are using these resource

Version-Release number of selected component (if applicable):

How reproducible:
always

Steps to Reproduce:(Storage add on as example)
1. subscribe storage add on , eg :3Gi;
2. Create a 1Gi pvc in openshift webconsole;
3. Try to downgrade storage to 0 on unified registration web console;

Actual results:
Downgrade succeed enevthough user are using storage.

Expected results:
Downgrade storage to 0 will failed. Storage/Memory/Terminating Memory add on  only can be downgraded to the used storage as the minium.In this  case, the minimum is 1Gi.


Additional info: