Wrong IEXEC_CORE_REQUIRED_WORKER_VERSION enforcement

[DamienMure]

Hi.
I upgraded my core:6.0.0 config to add:
IEXEC_CORE_REQUIRED_WORKER_VERSION=6.0.2
Even after core restart, my worker "6.0.0" is still able to connect to the core.

If "down/up" the worker, the expected behaviors occurs and the worker says:
Bad version! please upgrade your iexec-worker [current:6.0.0, required:6.0.2]

When you don't manger you worker, the core may be connected to unwanted workers as long as they do not reboot.