Revert recent py3 changes under ryu/contrib,
namely parts of the following commits:
- commit e2dfdbf580
("Treatment was not enough") and
- commit 325c9ae9c3
("Syntax level compatibility with Python 3")
Because:
- Some of them are broken (stream.py)
- Changes like these should go to upstream
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>