Description of problem: When adding resource on Environment page of VM, if Serial Number has unacceptable characters - error message does not disappear even when the resource is dismissed.

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

How reproducible: always

Steps to Reproduce:
1. Create or open a VM
2. Go to Environment tab
3. Click "Add Config Map, Secret or Service Account" link and select any type of resource
4. Add illegal character to Serial Number field, like # and click Save
5. After error message appears, remove the resource

Actual results: Error message stays

Expected results: Error message disappears

Additional info: