The function init_card catches all exceptions and then returns None
objects for card or rs in case of an error. This does not fit in the
style we pursue in pySim. This is in particular true for library
functions. We want those functions to raise exceptions when something is
wrong, so that we can catch the exception at top level. Let's fix this
for init_card now.
Related: OS#6271
Change-Id: I581125d8273ef024f6dbf3a5db6116be15c5c95d