When updating JobScheduler on Linux no Error "ConfigureEnvVars, null" should happen

Current Situation
When updating JobScheduler from 1.10.2 to 1.10.3 on a linux box, sometimes an error ConfigureEnvVars,null happens.

Desired Behaviour
Updating JobScheduler from 1.10.2 to 1.10.3 should work without error.

Maintainer Note

• The null in the alert should be the error message.
• It can not be excluded that an error occurs when updating the file ./bin/jobscheduler_environment_variables.sh, but it should then be logged an ordinary error message.