Recent Client changes

Changes in this pull:

* Removing two eception handlers in crab/bin: we were doing `except NameError` and `except KeyError`. With the new handling of the exceptionHook we don't need to catch them anymore (the stacktrace is not printed anymore)
* Fix #4267 
* Merge  @PerilousApricot pull request https://github.com/dmwm/CRABClient/pull/4242 which got out of date. Andrew, can you check if it sounds good? Thanks