Account for exception on closing a Dialog when the !DialogLevelManager tries to refocus the button that launched the Dialog, but gets an error.   Happens on page unload on IE when the dijit.form.Button that launched the Dialog is destroyed before the Dialog.   Fixes #15058 on trunk/ !strict.
Account for exception on closing a Dialog when the !DialogLevelManager tries to refocus the button that launched the Dialog, but gets an error.   Happens on page unload on IE when the dijit.form.Button that launched the Dialog is destroyed before the Dialog.   Fixes #15058 on trunk/ !strict.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@28212 560b804f-0ae3-0310-86f3-f6aa0a117693

redaktor/deliteful