Guido pointed out the problem with _fileobject.readline() being 
followed by socket.recv() if readline uses read buffering.  
xmlrpclib.py was attempting to directly use the underlying socket, 
although in actual fact it never did, (since HTTPConnectio had closed 
it when it returned the response from getresponse()) Never the less, it 
is prudent to make sure that we don't attempt this.
There really should be no need to use the socket directly, a buffered 
read() call is just as efficient.