Adjust travis emails

Author: Leonard Ehrenfried

.travis.yml

@@ -5,4 +5,7 @@ before_install: sudo apt-get install vim-gtk
 before_script:
   - "export DISPLAY=:99.0"
   - "sh -e /etc/init.d/xvfb start"
-
+notifications:
+  email:
+    on_success: never
+    on_failure: change