Handle JobQueueGroup::push throwing MWException

See also: I218b186

Change-Id: Ie3e4fd9b4d5b7141898008452c96572647154f23
(cherry picked from commit 4f7741907028f8291af3e878ab499def584bd2a9)
Merge "Handle JobQueueGroup::push throwing MWException" into mw1.24-wmf2