Revert "bottle: allow --keep-old to ignore same sha256s."

This reverts commit ec1437499a178a09805854469c5162d749270f3e.

Library/Homebrew/cmd/bottle.rb

@@ -391,14 +391,10 @@ module Homebrew
 
                 if !tag.empty?
                   if !bottle_hash["bottle"]["tags"][tag].to_s.empty?
-                    old_value = bottle_hash["bottle"]["tags"][tag][key].to_s
-                    if value != old_value
                     mismatches << "#{key} => #{tag}"
-                    end
+                  else
-                    next
-                  end
-
                     bottle.send(key, value => tag.to_sym)
+                  end
                   next
                 end