Show Node version if EXECJS_RUNTIME is Node

Author: guilleiguaran

.travis.yml

@@ -6,6 +6,7 @@ sudo: false
 before_install:
   - if [ "$EXECJS_RUNTIME" == "V8" ]; then brew update; fi
   - if [ "$EXECJS_RUNTIME" == "V8" ]; then brew install v8; fi
+  - if [ "$EXECJS_RUNTIME" == "Node" ]; then node --version; fi
   - if [ "$EXECJS_RUNTIME" == "MiniRacer" ]; then gem install bundler -v 1.12.0; fi
 script: bundle && bundle exec ruby test/test_execjs.rb