Use requests to read chunk data instead of parsing the raw stream

The previous code had a bug in which it assumed that the chunk data had
no newlines in it.  In 0.9.0 newlines were added to the stream results,
which exposed this bug.

docker/client.py

@@ -233,17 +233,8 @@ class Client(requests.Session):
 
     def _stream_helper(self, response):
         """Generator for data coming from a chunked-encoded HTTP response."""
-        socket_fp = self._get_raw_response_socket(response)
-        socket_fp.setblocking(1)
-        socket = socket_fp.makefile()
-        while True:
-            size = int(socket.readline(), 16)
-            if size <= 0:
-                break
-            data = socket.readline()
-            if not data:
-                break
-            yield data
+        for line in response.iter_lines(chunk_size=32):
+            yield line
 
     def _multiplexed_buffer_helper(self, response):
         """A generator of multiplexed data blocks read from a buffered