Removing old tox settings left from oauth2client

The oauth2client unit tests were removed, but some of the tox settings
were left straggling.  Removing them cleans up the config file a lot.
diff --git a/tox.ini b/tox.ini
index 6a3b10b..dd3380d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,16 +10,4 @@
        webtest
        nose
        unittest2
-setenv = PYTHONPATH=../google_appengine
-
-[testenv:py26]
-commands = nosetests --ignore-files=test_oauth2client_appengine\.py
-
-[testenv:py27]
-commands = nosetests
-
-[testenv:py33]
-commands = nosetests
-
-[testenv:py34]
 commands = nosetests