DPL: make --fairmq-ipc-prefix homogeneous (#5449)

It does not make sense to have more than one, because we have no
way to handle multiple locations.

Author: ktf

Framework/Core/src/runDataProcessing.cxx

@@ -1389,6 +1389,7 @@ int runStateMachine(DataProcessorSpecs const& workflow,
             "--aod-writer-resfile",
             "--aod-writer-resmode",
             "--driver-client-backend",
+            "--fairmq-ipc-prefix",
             "--readers",
             "--resources-monitoring",
             "--time-limit",