Revert "JS-1082 FIXED: When a job is started and the database is switched off the scheduler does not try to connect continuously" (denn JobHistory schreibt nach Datenbankfehler eine alte Task-ID, die schon verbraucht ist)

This reverts commit 6453c487221a3417274b3725a8c28fe68f39e3ed.
Merge branch 'release/1.5' into release/1.6