Force update Python

Author: astrofrog

.travis.yml

@@ -67,6 +67,7 @@ install:
     - if [[ $TRAVIS_OS_NAME == osx || $TRAVIS_OS_NAME == windows ]]; then
         git clone git://github.com/astropy/ci-helpers.git;
         source ci-helpers/travis/setup_conda.sh;
+        conda update python
       fi
 
 script: