Have travis use Ruby 2.0.0

Fix #17011

Update .travis.yml

.travis.yml

@@ -5,7 +5,8 @@ node_js:
   - "0.12"
 before_install:
   - travis_retry sudo pip install -r test-infra/requirements.txt
-  - rvm use 1.9.3 --fuzzy
+  - rvm install 2.0.0
+  - rvm use 2.0.0 --fuzzy
   - export GEMDIR=$(rvm gemdir)
   - if [ "$TWBS_TEST" = validate-html ]; then echo "ruby=$(basename $GEMDIR) jekyll=$JEKYLL_VERSION rouge=$ROUGE_VERSION" > pseudo_Gemfile.lock; fi
   - "export TRAVIS_COMMIT_MSG=\"$(git log --format=%B --no-merges -n 1)\""