TrigPSC: Release Python GIL after fork

When using Python-based algorithms (PyAthena, mainly for testing purposes) in the event loop we need to make sure that we release the Python Global Interpreter Lock (GIL) after the fork. Otherwise a deadlock occurs when PyAthenaAlg tries to acquire the GIL.

Also included a trivial fix to a DEBUG message in TrigServices.

This merge request affects 2 packages:

• HLT/Trigger/TrigControl/TrigPSC
• HLT/Trigger/TrigControl/TrigServices

Adding @wiedenma ,@bernius ,@fwinkl ,@rbielski as watchers

added Trigger master review-pending-level-1 labels

CI Result SUCCESS (hash 715a250e)

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 4369]

added review-approved label and removed review-pending-level-1 label

mentioned in commit af98f044

merged

added sweep:ignore label