* .travis.yml:  Rebuild Travis CI's "ruby-head" version on successful
  build.  Patch by Konstantin Haase.  [Fixes GH-417]
  https://github.com/ruby/ruby/pull/417


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43190 b2dd03c8-39d4-4d8f-98ff-823fe69b080e