Don't execute tests against "merge" commits
Don't execute tests against "merge" commits

Due to the way travis is built if any new tests for new functionality are added then the "merge" commit test will always fail. This is confusing as it means actually "green" tests have 1 failure. 

If we always exit on "merge" commits then we can expect green tests before actually merging pull requests



makifund/heroku-buildpack-ruby,pkgr/heroku-buildpack-ruby,ericboehs/heroku-buildpack-ruby,Genius/heroku-buildpack-ruby,Scalingo/ruby-buildpack,jonseaberg/heroku-buildpack-turbo-sprockets,ruby/heroku-buildpack-www-ruby-lang,Genius/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,ericboehs/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,andycroll/heroku-buildpack-jekyll,pilotcreative/heroku-buildpack-ruby,mattmanning/heroku-buildpack-ruby-jekyll,heroku/heroku-buildpack-ruby,Scalingo/ruby-buildpack,heroku/heroku-buildpack-ruby,andycroll/heroku-buildpack-jekyll,pilotcreative/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,makifund/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,zunda/heroku-buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,mattmanning/heroku-buildpack-ruby-jekyll,zunda/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,jonseaberg/heroku-buildpack-turbo-sprockets,pkgr/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby