Merge branch 'gitaly-commit-languages' into 'master'

.gitlab-ci.yml

GITALY_SERVER_VERSION

app/controllers/projects/graphs_controller.rb

lib/gitlab/git/repository.rb

lib/gitlab/gitaly_client/commit_service.rb

lib/tasks/gitlab/gitaly.rake

scripts/gitaly-test-build

scripts/gitaly-test-spawn

spec/controllers/projects/graphs_controller_spec.rb

spec/lib/gitlab/git/repository_spec.rb

spec/support/test_env.rb

spec/tasks/gitlab/gitaly_rake_spec.rb