Handle network errors during page refresh
    
    1. error.status == 0  - if network is down the reported status code is
       zero which bypasses some of our checks. Fixed by returning
       the entire error object.
    2. temporary network error causes VMs/pools to be removed from
       the dashboard. Fixed by removing only if the server reported 404.
    3. use common filtering routine to process VMs and pools retrieved
       during page refresh