Update tox dependency for pytest 2.9 to latest release

Author: davehunt

tox.ini

@@ -9,7 +9,7 @@ envlist = py{26,27,33,34,35,py,py3}-pytest{28,29}, flake8
 [testenv]
 deps =
     pytest28: pytest==2.8.7  # rq.filter: >=2.8,<2.9
-    pytest29: pytest==2.9.1
+    pytest29: pytest==2.9.2
     pytest-localserver
 commands = py.test -v -r a {posargs}