python: Check "buffer" when writing to sys.stdout for python2 compat.

* lang/python/tests/support.py (print_data): Add check for buffer.
--

When running with something like make -C lang/python check verbose=2 the
test would fail under python2, because the file objects do not have a
buffer property.

Signed-off-by: Tobias Mueller <muelli@cryptobitch.de>

lang/python/tests/support.py

@@ -48,7 +48,11 @@ def print_data(data):
         except:
             # Hope for the best.
             pass
-        sys.stdout.buffer.write(data)
+
+        if hasattr(sys.stdout, "buffer"):
+            sys.stdout.buffer.write(data)
+        else:
+            sys.stdout.write(data)
 
 def mark_key_trusted(ctx, key):
     class Editor(object):