Remove unused view

This was introduced in 2013 and removed in 2014, see log below:

git log -Saddress_form_simple
commit 510333288c
Author: Maikel Linke <mkllnk@web.de>
Date:   Sun Mar 2 13:05:15 2014 +1100

    first steps of new design

commit 2e1de9a6d3
Author: Rohan Mitchell <rohan@rohanmitchell.com>
Date:   Fri Aug 23 13:12:36 2013 +1000

    Fix admin create order - remove override on spree address form, update to spree patched to fix respond_override (spree issue #2210), fix nil state error

app/views/spree/admin/shared/_address_form_simple.html.haml

@@ -1,24 +0,0 @@
-%tr{"data-hook" => "address1"}
-  %td
-    = t(:admin_shared_address_1):
-  %td= f.text_field :address1
-%tr{"data-hook" => "address2" }
-  %td
-    = t(:admin_shared_address_2):
-  %td= f.text_field :address2
-%tr{"data-hook" => "city" }
-  %td
-    = t(:admin_share_city):
-  %td= f.text_field :city
-%tr{"data-hook" => "zipcode" }
-  %td
-    = t(:admin_share_zipcode):
-  %td= f.text_field :zipcode
-%tr{"data-hook" => "country" }
-  %td
-    = t(:admin_share_country):
-  %td= f.collection_select(:country_id, available_countries, :id, :name)
-%tr{"data-hook" => "state" }
-  %td
-    = t(:admin_share_state):
-  %td= f.collection_select(:state_id, f.object.country.states, :id, :name)