asyncio: pyflakes, remove unused import

tests: Remove unused function; inline another function

Lib/asyncio/base_events.py

@@ -636,7 +636,7 @@ def _create_connection_transport(self, sock, protocol_factory, ssl,
 
         try:
             yield from waiter
-        except Exception as exc:
+        except Exception:
             transport.close()
             raise