Rework exception handling
Rework exception handling

- Silence pylint about too broad exception, as this is the intended purpose
- Add a comment explaining just that
- Use the new form introduced in 2.6: "except Exc as exc_var_name"
  see : https://docs.python.org/3/whatsnew/2.6.html#pep-3110-exception-handling-changes

Pansanel/monitoring-os,FranceGrilles/monitoring-os