Protect member function call on FastMonitoringService pointer by testing whether or not it is nullptr; if so, store PB files in FU mode only for non-empty lumisections.
In fake FU, set explicitly process umask to 0.
In DQMStore, save files encoded with ProtocolBuffer by explicitly setting permissions to 0666.
In fastHadd, set file permissions to 0666 (as requested by DAQ2) for files merged and encoded with ProtolBuffer.
Merge pull request #4876 from diguida/fix_PB_file_permissions_v2

Fix file creations and permissions for DQM histograms encoded with ProtocolBuffer