When execution limit is reached it makes no sense to continue and
execute additional workers or log the execution limit exception as an error.
[MAILPOET-4725]
Sometimes errors overlap each other so that the 'Last Seen error' we log
does not provide sufficient information on the cause of a problem.
E.g. one worker might cause an SQL issue, which closes the EntityManager and a
subsequent worker might overwrite this error with the information that the
EntityManager is closed.
With this commit, both those issues will be logged as an error.
[MAILPOET-4699]
