Make stock locations backorderable_default false.

This is required because when the default stock location is created, the backorderable_default column doesnt exist and when this column is created, the initial default is true. This is why we need to force it to false here. This column is the default value for on_demand which must be false.

db/migrate/20190506194625_update_stock_locations_backorderable_default.rb

@@ -0,0 +1,5 @@
+class UpdateStockLocationsBackorderableDefault < ActiveRecord::Migration
+  def change
+    Spree::StockLocation.update_all(backorderable_default: false)
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20190504151144) do
+ActiveRecord::Schema.define(:version => 20190506194625) do
 
   create_table "adjustment_metadata", :force => true do |t|
     t.integer "adjustment_id"