Use flake8 in run_tests.sh and updated ignore flake8 rules with tox.ini

Change-Id: I9ec82e4ddbaa8c9f256ff962c48dfb556948b32d
Fixes: bug #1180609
Rename client.py to httpclient.py

The discoverable entry point is to be client.Client however adding this
functionality to the current client.py is impossible as we end up with
circular dependencies.

This patch simply renames the current client.py to httpclient.py to make
future patches that will modify client.py more readable.

Required for: blueprint api-version-discovery

Change-Id: Ibcea03f6e1df0ae05329297166a8b8117fc3ce7b
Merge "Use flake8 in run_tests.sh and updated ignore flake8 rules with tox.ini"
flake8: enable H201, H202, H802

Change-Id: I845720fd642c14fc021bd59809327eee97d43156
Merge "Rename client.py to httpclient.py"