Use relative import to include errors file

Author: jdecuyper

hyper/http20/connection.py

@@ -19,8 +19,8 @@
 from .response import HTTP20Response, HTTP20Push
 from .window import FlowControlManager
 from .exceptions import ConnectionError
+from . import errors
 
-import hyper.http20.errors as errors
 import errno
 import logging
 import socket