qvm-pool show pools without volumes

- Only empty `DomainPools` are skipped

qubes/tools/qvm_pool.py

@@ -85,9 +85,10 @@ def list_pools(app):
     ''' Prints out all known pools and their drivers '''
     result = [('NAME', 'DRIVER')]
     for pool in app.pools.values():
-        if len(pool.volumes) > 0 and not issubclass(
+        if len(pool.volumes) == 0 and issubclass(
                 pool.__class__, qubes.storage.domain.DomainPool):
             # skip empty DomainPools
+            continue
         result += [(pool.name, pool.driver)]
     qubes.tools.print_table(result)