Update travis-ci matrix to use Python 3.4 istead of Python 3.3.

epels · epels · commit ce73bb450be6 · 2019-06-19T12:43:18.000+02:00
Travis updated their default distro to 16.04, which does not have
a 3.3 tarball
diff --git a/.travis.yml b/.travis.yml
@@ -3,7 +3,7 @@ python:
   - 'pypy2.7'
   - 'pypy3.5'
   - '2.7'
-  - '3.3'
+  - '3.4'
   - '3.6'
   - 'nightly'
 install:
