Fix 404 error handling issue.

git-svn-id: https://plugins.svn.wordpress.org/better-font-awesome/trunk@973660 b8457f37-d9ea-0310-8a92-e5e31aec5664
Improve 404 error handling.

git-svn-id: https://plugins.svn.wordpress.org/better-font-awesome/trunk@973664 b8457f37-d9ea-0310-8a92-e5e31aec5664