Switch default gravatar to identicon

Author: themightychris

php-config/Laddr.config.d/gravatar.php

@@ -5,4 +5,4 @@
  * see: http://en.gravatar.com/site/implement/images/
  * mm (mystery-man), identicon, monsterid, wavatar, retro, blank
  */
-Laddr::$gravatarDefault = 'mm';
+Laddr::$gravatarDefault = 'identicon';