Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.

Fix problems found.

Change-Id: I6a4340d71e934cad5d9c2337e4728c6900fdd924

test-requirements.txt

@@ -7,7 +7,7 @@
 # be installed in a specific order.
 #
 # Hacking should appear first in case something else depends on pep8
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+hacking>=3.0,<3.1.0 # Apache-2.0
 
 coverage!=4.4,>=4.0 # Apache-2.0
 mock>=2.0.0 # BSD

tools/install_venv.py

@@ -67,5 +67,6 @@ def main(argv):
     install.install_dependencies()
     print_help(venv, root)
 
+
 if __name__ == '__main__':
     main(sys.argv)

tox.ini

@@ -37,7 +37,8 @@ commands = flake8 {posargs}
 [flake8]
 # F405 TEMPLATES may be undefined, or defined from star imports
 # (because it is not easy to avoid this in openstack_dashboard.test.settings)
-ignore = F405
+# W504 line break after binary operator
+ignore = F405,W504
 exclude = .venv,.git,.tox,dist,*egg,build,node_modules
 max-complexity = 20