Merge branch 'failedrequest' into 'master'

ReleaseNotes.md

cmdline/CtaAdminCmdParse.hpp

scheduler/OStoreDB/OStoreDB.cpp

scheduler/OStoreDB/OStoreDB.hpp

scheduler/OStoreDB/OStoreDBFactory.hpp

scheduler/Scheduler.cpp

scheduler/Scheduler.hpp

scheduler/SchedulerDatabase.hpp

xroot_plugins/XrdSsiCtaRequestMessage.cpp

xroot_plugins/XrdSsiCtaRequestMessage.hpp

xrootd-ssi-protobuf-interface