Disable environment list polling as it breaks deployboard

app/controllers/projects/environments_controller.rb

@@ -15,8 +15,6 @@ class Projects::EnvironmentsController < Projects::ApplicationController
     respond_to do |format|
       format.html
       format.json do
-        Gitlab::PollingInterval.set_header(response, interval: 3_000)
-
         render json: {
           environments: EnvironmentSerializer
             .new(project: @project, current_user: @current_user)

changelogs/unreleased/disable-environment-list-refresh.yml

+---
+title: Disable environment list refresh due to bug https://gitlab.com/gitlab-org/gitlab-ee/issues/2677
+merge_request: 12347
+author:

spec/controllers/projects/environments_controller_spec.rb

@@ -58,9 +58,11 @@ describe Projects::EnvironmentsController do
           expect(json_response['stopped_count']).to eq 1
         end
 
-        it 'sets the polling interval header' do
+        it 'does not set the polling interval header' do
+          # TODO, this is a temporary fix, see follow up issue:
+          # https://gitlab.com/gitlab-org/gitlab-ee/issues/2677
           expect(response).to have_http_status(:ok)
-          expect(response.headers['Poll-Interval']).to eq("3000")
+          expect(response.headers['Poll-Interval']).to be_nil
         end
       end