Remove dead method in payment method, it's a scope in OFN and remove unnecessary comments about spree

app/models/spree/credit_card.rb

@@ -2,8 +2,6 @@
 
 module Spree
   class CreditCard < ActiveRecord::Base
-    # Should be able to remove once we reach Spree v2.2.0
-    # https://github.com/spree/spree/commit/411010f3975c919ab298cb63962ee492455b415c
     belongs_to :payment_method
     belongs_to :user
 

app/models/spree/payment_method.rb

@@ -13,7 +13,7 @@ module Spree
     DISPLAY = [:both, :front_end, :back_end].freeze
     default_scope -> { where(deleted_at: nil) }
 
-    has_many :credit_cards, class_name: "Spree::CreditCard" # from Spree v.2.3.0 d470b31798f37
+    has_many :credit_cards, class_name: "Spree::CreditCard"
 
     validates :name, presence: true
     validate :distributor_validation
@@ -22,7 +22,6 @@ module Spree
 
     scope :production, -> { where(environment: 'production') }
 
-    # -- Scopes
     scope :managed_by, lambda { |user|
       if user.has_spree_role?('admin')
         where(nil)
@@ -48,7 +47,6 @@ module Spree
 
     scope :by_name, -> { order('spree_payment_methods.name ASC') }
 
-    # Rewrite Spree's ruby-land class method as a scope
     scope :available, lambda { |display_on = 'both'|
       where(active: true).
         where('spree_payment_methods.display_on=? OR spree_payment_methods.display_on=? OR spree_payment_methods.display_on IS NULL', display_on, '').
@@ -70,14 +68,6 @@ module Spree
       raise 'You must implement payment_source_class method for this gateway.'
     end
 
-    def self.available(display_on = 'both')
-      all.select do |p|
-        p.active &&
-          (p.display_on == display_on.to_s || p.display_on.blank?) &&
-          (p.environment == Rails.env || p.environment.blank?)
-      end
-    end
-
     def self.active?
       where(type: to_s, environment: Rails.env, active: true).count.positive?
     end