More specific grace_course logging

lms/djangoapps/instructor_task/tasks_helper/grades.py

@@ -191,7 +191,11 @@ class CourseGradeReport(object):
         batched_rows = self._batched_rows(context)
 
         context.update_status(u'Compiling grades')
-        success_rows, error_rows = self._compile(context, batched_rows)
+        try:
+            success_rows, error_rows = self._compile(context, batched_rows)
+        except Exception:  # pylint:disable=broad-except
+            TASK_LOG.exception('Something failed in compilation')
+            return context.update_status('Failed grades')
 
         context.update_status(u'Uploading grades')
         self._upload(context, success_headers, success_rows, error_headers, error_rows)