WatchList send an exception by mail

For 1.3 and 1.5, if there is an issue with rigths when WatchListMessage retrieve a document with $xwiki.getDocument, than the $udoc is null and an exception is thrown when $formatDate($udoc.date) is executed. This exception is send in the notification mail. I feel that $udoc should be test for null and take an appropriate action.

This has happen to me due to an issue with the jobs in the Scheduler that were missing the contextUser and other context information, after an upgrade from 1.3 to 1.4. While testing why this happen, the missing fields has appeared after a container restart, however the issue persist for now. I am tracking that further right now.