Modify hacking flake8 extension

Move hacking files to dir used by the rest of the projects
Use the hacking factory option to allow for additional checks

Change-Id: If498bb4a2d1ce85c51abd04a559e9106febf4027

tempest/hacking/checks.py

@@ -40,3 +40,7 @@ def skip_bugs(physical_line):
 
         if bug_re.match(physical_line) is None:
             return (pos, 'T102: Bug number formatted incorrectly')
+
+
+def factory(register):
+    register(skip_bugs)

tox.ini

@@ -60,7 +60,7 @@ deps = -r{toxinidir}/tools/pip-requires
        -r{toxinidir}/tools/test-requires
 
 [hacking]
-local-check = tools.hacking.tempest.skip_bugs
+local-check-factory = tempest.hacking.checks.factory
 
 [flake8]
 ignore = E125,H302,H404