trema/trema — pull request #345 by masap (2014-01-16 07:22:34+00:00)
Title: Use separate Packet Out for learning switch C example

Currently learning switch C example sends Flow Mod with valid buffer_id.
But the style is noted as dangerous in [1].
This patch separates Flow Mod and Packet Out.

[1] https://github.com/yasuhito/trema-book/blob/master/ja/openflow_spec.re