Backport new behavior to CI API

lib/ci/api/builds.rb

@@ -217,6 +217,7 @@ module Ci
           build = Ci::Build.find_by_id(params[:id])
           authenticate_build!(build)
+          status(200)
           build.erase_artifacts!
         end
       end

lib/ci/api/runners.rb

@@ -8,6 +8,8 @@ module Ci
         end
         delete "delete" do
           authenticate_runner!
+
+          status(200)
           Ci::Runner.find_by_token(params[:token]).destroy
         end