Make sure a NotImplementedError is always raised on Connection.makefile() (#744)

* Make sure a NotImplementedError is always raised on Connection.makefile

With this patch, code which calls (for example) conn.makefile('rb') will
get a NotImplementedError instead of a confusing TypeError:

    TypeError: makefile() takes 1 positional argument but 2 were given

* ignore any args/kwargs passed
diff --git a/src/OpenSSL/SSL.py b/src/OpenSSL/SSL.py
index 8d8cfe3..4c708ba 100644
--- a/src/OpenSSL/SSL.py
+++ b/src/OpenSSL/SSL.py
@@ -2039,7 +2039,7 @@
             result.append(pyname)
         return result
 
-    def makefile(self):
+    def makefile(self, *args, **kwargs):
         """
         The makefile() method is not implemented, since there is no dup
         semantics for SSL connections