Merged requested to merge jchapman/athena:BCM_DigitizationMTRNG into master
In order for digitization output to be reproducible in AthenaMT the digitization code must be migrated to use the thread-safe random number service. Sub-system digitization code can be migrated one sub-system at a time. Decided to start with BCM as this is the simplest case. Local tests show that the digitization jobs run OK.