Low: scheduler: improve "friendly" failed action output

Change:

• rsc1 start on node1 could not be executed (Timed Out) because 'Investigate reason for timeout, and adjust configured operation timeout if necessary' at Fri Jan 21 10:23:15 2022 after 4.982s

to:

• rsc1 start on node1 could not be executed (Timed Out: Investigate reason for timeout, and adjust configured operation timeout if necessary) at Fri Jan 21 10:23:15 2022 after 4.982s

which is more readable and consistent with log messages elsewhere.