Changed the type of Error occurring when no valid sender could be found to a FatalJobError in student_proposal_mailer.
This means that the job will be immediately aborted.
This patch is due to comments on r3000 by SRabbelier.
Patch by: Lennard de Rijk
Reviewed by: to-be-reviewed
Coverage: code coverage testing for Python
Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.
For more information, see http://nedbatchelder.com/code/modules/coverage.html