Remove StockLocation from ReturnAuthorization

We have only one default location and don't need it associated to
anything.

app/controllers/spree/admin/return_authorizations_controller.rb

@@ -23,7 +23,7 @@ module Spree
 
       def permitted_resource_params
         params.require(:return_authorization).
-          permit(:amount, :reason, :stock_location_id)
+          permit(:amount, :reason)
       end
     end
   end

app/models/spree/return_authorization.rb

@@ -2,12 +2,12 @@
 
 module Spree
   class ReturnAuthorization < ApplicationRecord
+    self.ignored_columns += [:stock_location_id]
     acts_as_paranoid
 
     belongs_to :order, class_name: 'Spree::Order', inverse_of: :return_authorizations
 
     has_many :inventory_units, inverse_of: :return_authorization, dependent: :nullify
-    has_one :stock_location, dependent: nil
     before_save :force_positive_amount
     before_create :generate_number
 

app/views/spree/admin/return_authorizations/_form.html.haml

@@ -41,8 +41,3 @@
     = f.label :reason, t('.reason')
     = f.text_area :reason, { style: 'height:100px;', class: 'fullwidth' }
     = f.error_message_on :reason
-
-  = f.field_container :stock_location do
-    = f.label :stock_location, t('.stock_location')
-    = f.select :stock_location_id, Spree::StockLocation.all.collect{ |l| [l.name, l.id] }, { style: 'height:100px;', class: 'fullwidth' }
-    = f.error_message_on :reason