Fix some packages in requirements.txt and test-requirements.txt are too
old and causing a failure in `tox -e pep8`. It also fixes invalid styles
treated as an error in the recent flake8's checking.
Change-Id: I68989196a962469b4f74e5120431fc18804ea465
Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com>