Switch to hacking 2.x

This bumps the version of flake8 and pycodestyle to something much
newer, which resolves a long-standing warning about nested sets and
allows us to use new fangled features like f-strings if we so choose.

Note that this requires some minor modifications to keep the 'pep8' task
passing.

Change-Id: I3af8eb490345a6152372730ca3e0a6702bf482ea
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

lower-constraints.txt

@@ -11,7 +11,7 @@ fixtures==3.0.0
 flake8==2.5.5
 gitdb==0.6.4
 GitPython==1.0.1
-hacking==0.12.0
+hacking==2.0.0
 imagesize==0.7.1
 iso8601==0.1.11
 Jinja2==2.10

oslo_config/_i18n.py

@@ -37,4 +37,4 @@ _P = _translators.plural_form
 
 
 def get_available_languages():
-        return oslo_i18n.get_available_languages(DOMAIN)
+    return oslo_i18n.get_available_languages(DOMAIN)

oslo_config/tests/test_cfg.py

@@ -2893,7 +2893,7 @@ class TemplateSubstitutionTestCase(BaseTestCase):
 
         paths = self.create_tempfiles([('test',
                                         '[DEFAULT]\n'
-                                        'bar=foo-somethin\$k2\n')])
+                                        'bar=foo-somethin\\$k2\n')])
 
         self.conf(['--config-file', paths[0]])
 

test-requirements.txt

@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+hacking>=2.0.0,<2.1.0 # Apache-2.0
 
 fixtures>=3.0.0 # Apache-2.0/BSD
 testscenarios>=0.4 # Apache-2.0/BSD