Revert "Can we even ask for Python 2.4 on Travis?"

Becaue we can't: https://travis-ci.org/mgedmin/ansible/jobs/84866458

This reverts commit e31e866e.

.travis.yml

@@ -3,7 +3,6 @@ language: python
 matrix:
   include:
     - env: TOKENV=py24 INTEGRATION=no
-      python: 2.4
     - env: TOXENV=py26 INTEGRATION=yes
       python: 2.6
     - env: TOXENV=py27 INTEGRATION=yes