Regulation plot is failing with an exception

When FLint is closed before the regulation loop, the loop fail with an exception due to a wrong use of the log API.

                  Traceback (most recent call last):
                    File "src/gevent/greenlet.py", line 906, in gevent._gevent_cgreenlet.Greenlet.run
                    File "/home/pguillou/bliss/bliss/common/regulation.py", line 2111, in run
                      log_debug(self, "Error while plotting the data", exc_info=True)
                  TypeError: log_debug() got an unexpected keyword argument 'exc_info'