I believe the the schedule change is because of the situation in Bahrain, where the flight continues on to after the stop in DOH.
On that basis, it might be fair to assume that it was BA's choice to reschedule, all be it for the best of motives, i.e. to operate outside of the BAH curfew.
Whether the situation in BAH now justifies the schedule change is a matter for conjecture.
hth