Search case-insensitively in `mailaprop-matches'

This was always my intent; I'd just typo'd the `case-fold-search' binding.

mailaprop.el

@@ -424,7 +424,7 @@ worth it to avoid just this one duplication."
 Return the list of matching contacts"
   (interactive "sSearch email contacts: \nP")
   (let ((matches ())
-        (case-fold-search nil))
+        (case-fold-search t))
     (mapcar
      (lambda (elt)
        (let ((candidate (mailaprop-ae-get-addr elt)))