<bugfix>Looping over a failing PythonSource caused logger to fail</bugfix>
<bugfix>Looping over a failing PythonSource caused logger to fail</bugfix>

core/log/controller.py:
- LogController.finish_module_execution:
  Skip if .module_exec is missing

hjanime/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,minesense/VisTrails,celiafish/VisTrails,minesense/VisTrails,VisTrails/VisTrails,minesense/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,hjanime/VisTrails,Nikea/VisTrails,minesense/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,hjanime/VisTrails,celiafish/VisTrails,Nikea/VisTrails