Use EE to contain EE constants

ee/app/helpers/license_helper.rb

@@ -22,7 +22,7 @@ module LicenseHelper
 
     message << expiration_message
 
-    message << link_to('Buy now!', Gitlab::SUBSCRIPTIONS_PLANS_URL, target: '_blank') if is_trial
+    message << link_to('Buy now!', ::EE::SUBSCRIPTIONS_PLANS_URL, target: '_blank') if is_trial
 
     if current_license.expired? && current_license.will_block_changes?
       message << 'Pushing code and creation of issues and merge requests'
@@ -69,7 +69,7 @@ module LicenseHelper
 
   def new_trial_url
     return_to_url = CGI.escape(Gitlab.config.gitlab.url)
-    uri = URI.parse(Gitlab::SUBSCRIPTIONS_URL)
+    uri = URI.parse(::EE::SUBSCRIPTIONS_URL)
     uri.path = '/trials/new'
     uri.query = "return_to=#{return_to_url}"
     uri.to_s

ee/app/views/admin/licenses/_upload_buy_license.html.haml

-= link_to 'Buy License', Gitlab::SUBSCRIPTIONS_PLANS_URL, target: '_blank', rel: 'noopener noreferrer nofollow', class: "btn btn-new btn-inverted pull-right btn-buy-license"
+= link_to 'Buy License', ::EE::SUBSCRIPTIONS_PLANS_URL, target: '_blank', rel: 'noopener noreferrer nofollow', class: "btn btn-new btn-inverted pull-right btn-buy-license"
 = link_to 'Upload New License', new_admin_license_path, class: "btn pull-right btn-upload-license append-right-10"

ee/app/views/shared/promotions/_promotion_link_project.html.haml

@@ -10,7 +10,7 @@
     %p Contact owner #{ link_to(owner.name, user_path(owner)) } to upgrade the plan.
 - elsif current_user&.admin?
   - if License.current&.expired?
-    = link_to (!short_form ? 'Buy GitLab Enterprise Edition' : 'Buy EE'), Gitlab::SUBSCRIPTIONS_PLANS_URL, class: 'btn btn-primary'
+    = link_to (!short_form ? 'Buy GitLab Enterprise Edition' : 'Buy EE'), ::EE::SUBSCRIPTIONS_PLANS_URL, class: 'btn btn-primary'
   - else
     = link_to (!short_form ? 'Start GitLab Ultimate trial' : 'Start GitLab Ultimate trial'), new_trial_url, class: 'btn btn-primary'
 - else

ee/lib/ee.rb

+module EE
+  SUBSCRIPTIONS_URL = 'https://customers.gitlab.com'.freeze
+  SUBSCRIPTIONS_PLANS_URL = "#{SUBSCRIPTIONS_URL}/plans".freeze
+end

lib/gitlab.rb

@@ -15,11 +15,6 @@ module Gitlab
   VERSION = File.read(root.join("VERSION")).strip.freeze
   REVISION = Gitlab::Popen.popen(%W(#{config.git.bin_path} log --pretty=format:%h -n 1)).first.chomp.freeze
 
-  # EE constants START
-  SUBSCRIPTIONS_URL = 'https://customers.gitlab.com'.freeze
-  SUBSCRIPTIONS_PLANS_URL = "#{SUBSCRIPTIONS_URL}/plans".freeze
-  # EE constants END
-
   def self.com?
     # Check `gl_subdomain?` as well to keep parity with gitlab.com
     Gitlab.config.gitlab.url == COM_URL || gl_subdomain?