tox.ini: fix checkqa in envlist (#646)

Fixes #567.

Author: blueyed

tox.ini

@@ -4,7 +4,7 @@ envlist =
     py34-dj{20,111,110}-postgres
     py27-dj{111,110}-{mysql_innodb,mysql_myisam,postgres}
     py27-dj{111,110,19,18}-postgres
-    py{36,py27}-checkqa
+    checkqa
 
 [testenv]
 extras = testing