Fix bug in FCKEditor where a legitimate security error encountered on bootstrap would break the editor.

To repro: Use chrome 30.0.1599.101, clear cache, and load an FCKEditor
which has an iframe whose origin is cross-domain. The FCKEditor will
fail to load.

http://support.addthis.com/customer/portal/questions/3329856-uncaugh-security-error-breaks-fck-editor