Description of problem:

Create new project and edit quota failed with below error:

Quota value(s) cannot be less than the current usage value(s):
131072RAM(MB) used. 11 instance used. 52 VCPUs used.

This issue is reported in upstream: 
https://bugs.launchpad.net/horizon/+bug/1380701

And also reported on Juno version:
https://bugzilla.redhat.com/show_bug.cgi?id=1198564


Version-Release number of selected component (if applicable):
- RHOSP 10
- python-django-horizon-10.0.2-1.el7ost.noarch                



How reproducible:


Steps to Reproduce:
1. Create new project in admin portal with identity --> project
2. Edit project and set quota 
3. 

Actual results:
Edit project quota failed with error"Quota value(s) cannot be less than the current usage value(s):..."

Expected results:
Edit project quota should be succeed without error. 

Additional info: