Fix edit.php row action redirects when referrers are not sent. Return false...

Fix edit.php row action redirects when referrers are not sent.  Return false from wp_get_referer() when no referrer found. Props mitchoyoshitaka. fixes #17628

git-svn-id: https://core.svn.wordpress.org/trunk@19272 1a063a9b-81f0-0310-95a4-ce76da25c4cd