Move `legacy_cache` outside of `Locations`.

Library/Homebrew/cask/lib/hbc/cache.rb

@@ -10,10 +10,11 @@ module Hbc
     end
 
     def delete_legacy_cache
-      return unless Hbc.legacy_cache.exist?
+      legacy_cache = HOMEBREW_CACHE.join("Casks")
+      return unless legacy_cache.exist?
 
-      ohai "Deleting legacy cache at #{Hbc.legacy_cache}..."
-      FileUtils.remove_entry_secure(Hbc.legacy_cache)
+      ohai "Deleting legacy cache at #{legacy_cache}..."
+      FileUtils.remove_entry_secure(legacy_cache)
     end
   end
 end

Library/Homebrew/cask/lib/hbc/locations.rb

@@ -38,10 +38,6 @@ module Hbc
         end
       end
 
-      def legacy_cache
-        @legacy_cache ||= HOMEBREW_CACHE.join("Casks")
-      end
-
       attr_writer :cache
 
       def cache