added :zap for filezilla

Closes #9523.

Casks/filezilla.rb

@@ -15,6 +15,11 @@ cask :v1 => 'filezilla' do
   license :gpl
 
   app 'FileZilla.app'
-  # todo verify that this does not contain user-generate content
+
-  # zap :delete => '~/.filezilla'
+  zap :delete => [
+                  '~/Library/Saved Application State/de.filezilla.savedState',
+                  '~/Library/Preference/de.filezilla.plist',
+                 ],
+      :rmdir => '~/.config/filezilla'
+
 end