fix up a forced long line

tests/crypto/test_keyring.py

@@ -60,8 +60,9 @@ class KeyringTestCase(unittest.TestCase):
         self.hs = yield utils.setup_test_homeserver(
             handlers=None, http_client=self.http_client
         )
+        keys = self.mock_perspective_server.get_verify_keys()
         self.hs.config.perspectives = {
-            self.mock_perspective_server.server_name: self.mock_perspective_server.get_verify_keys()
+            self.mock_perspective_server.server_name: keys
         }
 
     def check_context(self, _, expected):