patch for py-amqp under python3 not to add bytes to str

gistfile1.txt

diff --git a/amqp/transport.py b/amqp/transport.py
index 8092c5f..e9ee76a 100644
--- a/amqp/transport.py
+++ b/amqp/transport.py
@@ -191,7 +191,7 @@
         as you're asking for, at least with extremely large messages.
         somewhere > 16K - found this in the test_channel.py test_large
         unittest."""
-        result = ''
+        result = b''
 
         while len(result) < n:
             try: