run_test.sh:
* run pylint on virtualenv to enforce version 0.25.0 for now.
(because pylint 0.25.1 doesn't work due to a bug)
* output pep8.log for Jenkins integration.
pylint:
* disable some noisy messages.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>