Description of problem:
Stacks do not honour the tags visibility

Version-Release number of selected component (if applicable):
5.4.4.2.20151130143928_89a28ce

How reproducible:
Very

Steps to Reproduce:
1. Create a new Role
2. Create a new Group with Tag "My Company Tags" in the Associate Filters section
3. Create a new user with the above group
4. Navigate to Clouds ==> Stacks
5. Choose a stack and assign the some tag to it
6. Login as the created user and check for Cloud Stack visibility

Actual results:
Displays all the Stacks.

Expected results:
Should display the stack whose tag matches with User's Group tag

Additional info: