Fix warning after icon has successfully been moved.

classes/pref/feeds.php

@@ -502,7 +502,7 @@ class Pref_Feeds extends Handler_Protected {
 			$rc = 2;
 		}
 
-		@unlink($icon_file);
+		if (is_file($icon_file)) @unlink($icon_file);
 
 		print "<script type=\"text/javascript\">";
 		print "parent.CommonDialogs.uploadIconHandler($rc);";