Prevent notice "Undefined variable: struct" in mt_getRecentPostTitles when...

Prevent notice "Undefined variable: struct" in mt_getRecentPostTitles when posts exist, but none of them are editable. Fixes #20393.


git-svn-id: https://core.svn.wordpress.org/trunk@20403 1a063a9b-81f0-0310-95a4-ce76da25c4cd