breadcrumbs: check for view.koDoc.file being null.

This can happen if a new file has never been saved.

(integrated from komodo (trunk) change 81312 by marky)

git-svn-id: http://svn.openkomodo.com/repos/openkomodo/trunk@13395 b87d16e7-d29f-4ee1-b5ec-817d645d335f