Ensure GitLab CI project exists when CI service is activated manually

When I check activeated checkbox in project services for GitLab CI it
cause half-working state when gitlab_ci_project is missing. This patch
fixes it until we have proper behaviour implemented later
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/models/project_services/gitlab_ci_service.rb

@@ -22,12 +22,17 @@ class GitlabCiService < CiService
   include Gitlab::Application.routes.url_helpers
 
   after_save :compose_service_hook, if: :activated?
+  after_save :ensure_gitlab_ci_project, if: :activated?
 
   def compose_service_hook
     hook = service_hook || build_service_hook
     hook.save
   end
 
+  def ensure_gitlab_ci_project
+    project.ensure_gitlab_ci_project
+  end
+
   def supported_events
     %w(push tag_push)
   end