Issue #1723828 by hass: Fixed Rename theme key to theme hook in error message.

core/includes/theme.inc

@@ -913,7 +913,7 @@ function theme($hook, $variables = array()) {
       // Only log a message when not trying theme suggestions ($hook being an
       // array).
       if (!isset($candidate)) {
-        watchdog('theme', 'Theme key "@key" not found.', array('@key' => $hook), WATCHDOG_WARNING);
+        watchdog('theme', 'Theme hook %hook not found.', array('%hook' => $hook), WATCHDOG_WARNING);
       }
       return '';
     }