fix typo

git-svn-id: https://plugins.svn.wordpress.org/bbpress-notify-nospam/trunk@932141 b8457f37-d9ea-0310-8a92-e5e31aec5664
fix typo from trunk

git-svn-id: https://plugins.svn.wordpress.org/bbpress-notify-nospam/branches/1.5@932143 b8457f37-d9ea-0310-8a92-e5e31aec5664