logs(stream=True) broken for python 3.3
I'm unable to iterate over logs as a stream for a container in python 3.3. It seems like some of the private apis have changed. I poked around for a minute but this is over my head. I pip installed the master.zip on commit ef009e114a3be

Code to reproduce:

``` python
for chunk in d.logs(c, stream=True):
    print(chunk)
```

Error

``` python
 Traceback (most recent call last):
   File "/home/m/Code/dockerstuff/d.py", line 100, in main
     for chunk in d.logs(c, stream=True):
   File "/home/m/.virtualenvs/d/lib/python3.3/site-packages/docker/client.py", line 257, in _multiplexed_socket_stream_helper
     socket = self._stream_result_socket(response)
   File "/home/m/.virtualenvs/d/lib/python3.3/site-packages/docker/client.py", line 226, in _stream_result_socket
     return response.raw._fp.fp._sock
AttributeError: '_io.BufferedReader' object has no attribute '_sock'
```

diff --git a/docker/client.py b/docker/client.py
index b1c85800..8cd2f535 100644
--- a/docker/client.py
+++ b/docker/client.py
@@ -228,7 +228,10 @@ class Client(requests.Session):
 
     def _get_raw_response_socket(self, response):
         self._raise_for_status(response)
-        return response.raw._fp.fp._sock
+        if six.PY3:
+            return response.raw._fp.fp.raw._sock
+        else:
+            return response.raw._fp.fp._sock
 
     def _stream_helper(self, response):
         """Generator for data coming from a chunked-encoded HTTP response."""
@@ -264,14 +267,19 @@ class Client(requests.Session):
         socket = self._get_raw_response_socket(response)
 
         def recvall(socket, size):
-            data = ''
+            blocks = []
             while size > 0:
                 block = socket.recv(size)
                 if not block:
                     return None
 
-                data += block
+                blocks.append(block)
                 size -= len(block)
+
+            sep = bytes() if six.PY3 else str()
+            data = sep.join(blocks)
+            if six.PY3:
+                data = data.decode('utf-8')
             return data
 
         while True:
['docker/client.py']