Add pyc cleanup and black check to tox

Change-Id: Ie9343ea5993f9075fdae7f8d6e965095b59d4fb2

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py3,pep8,cover_report
+envlist = py3,pep8,black_check,cover_report
 skipsdist = True
 minversion = 3.1.1
 ignore_basepython_conflict = True
@@ -11,8 +11,12 @@ deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
-commands = adjutant-api test {posargs}
+commands =
+    find adjutant -type f -name "*.pyc" -delete
+    adjutant-api test {posargs}
 setenv = VIRTUAL_ENV={envdir}
+whitelist_externals =
+  find
 
 [testenv:pep8]
 commands =