tox: fix checkqa: flake8 was not run (#515)

Author: blueyed

tox.ini

@@ -36,11 +36,10 @@ setenv =
      PYTHONPATH = {toxinidir}:{env:PYTHONPATH:}
 
 usedevelop = True
-whitelist_externals =
-    sh
 
 commands =
-    checkqa: flake8 --version && flake8 --show-source --statistics
+    checkqa: flake8 --version
+    checkqa: flake8 --show-source --statistics {posargs:pytest_django pytest_django_test}
     mysql_innodb: py.test --ds=pytest_django_test.settings_mysql_innodb --strict -r fEsxXw {posargs:tests}
     mysql_myisam: py.test --ds=pytest_django_test.settings_mysql_myisam --strict -r fEsxXw {posargs:tests}
     postgres: py.test --ds=pytest_django_test.settings_postgres --strict -r fEsxXw {posargs:tests}