fix tests as env query is now changed due to new rubocop

test/support/storage_helpers.rb

@@ -213,6 +213,9 @@ def mock_env(hash)
           hash[key]
         end
         allow(ENV).to receive(:keys).and_return hash.keys
+        allow(ENV).to receive(:fetch) do |key, default|
+          hash[key] || default
+        end
         # reset the ENV cache
         Y2Storage::StorageEnv.instance.send(:initialize)
       end