Description of problem: In VirtualMachines page filtering by OS shows '0' for all OSes. If some OS is selected, list becomes empty.

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

How reproducible: always

Steps to Reproduce:
1. Open VirtualMachines page
2. Create different OS VMs if there no
3. Open Filter dropdown menu and scroll to "Operating systems" section

Actual results: All OSes have zeroes as counters, any selection empties the VM list

Expected results: Counters are according to existing VMs, filtering works properly

Additional info: