Add new tests for different cases:

  -If an exception is raised when sending mail, the error is not lost
   (available in zope event.log)
  -If an exception is raised when using the site error logger, the error is not
   lost. This test passes for SQLDict, but fails if activity is SQLQueue
  -If a traceback could not be generated, a mail can still be sent


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@34819 20353a03-c40f-0410-a6d1-a30d3c3de9de