transport: do not catch exceptions in init_reader

We currently catch any exceptions that may occur when the card reader is
initialized. Then we print the exception string or the exception type
when no string is available. However, a failure during the reader
initialization is usually a severe problem, so a traceback would provde
a lot of helpful information to debug the issue. So lets not catch any
exceptions at this level so that we get the full backtrace.

Related: OS#6210
Change-Id: I4c4807576fe63cf71a7d33b243a3f8fea0b7ff23

pySim-prog.py

@@ -794,8 +794,6 @@ if __name__ == '__main__':
 
     # Init card reader driver
     sl = init_reader(opts)
-    if sl is None:
-        exit(1)
 
     # Create command layer
     scc = SimCardCommands(transport=sl)

pySim-read.py

@@ -74,8 +74,6 @@ if __name__ == '__main__':
 
     # Init card reader driver
     sl = init_reader(opts)
-    if sl is None:
-        exit(1)
 
     # Create command layer
     scc = SimCardCommands(transport=sl)

pySim-shell.py

@@ -1015,8 +1015,6 @@ if __name__ == '__main__':
 
     # Init card reader driver
     sl = init_reader(opts, proactive_handler = Proact())
-    if sl is None:
-        exit(1)
 
     # Create a card handler (for bulk provisioning)
     if opts.card_handler_config:

pySim/transport/__init__.py

@@ -292,12 +292,10 @@ def argparse_add_reader_args(arg_parser):
     return arg_parser
 
 
-def init_reader(opts, **kwargs) -> Optional[LinkBase]:
+def init_reader(opts, **kwargs) -> LinkBase:
     """
     Init card reader driver
     """
-    sl = None  # type : :Optional[LinkBase]
-    try:
     if opts.pcsc_dev is not None:
         print("Using PC/SC reader interface")
         from pySim.transport.pcsc import PcscSimLink
@@ -317,10 +315,3 @@ def init_reader(opts, **kwargs) -> Optional[LinkBase]:
         sl = SerialSimLink(device=opts.device,
                            baudrate=opts.baudrate, **kwargs)
     return sl
-    except Exception as e:
-        if str(e):
-            print("Card reader initialization failed with exception:\n" + str(e))
-        else:
-            print(
-                "Card reader initialization failed with an exception of type:\n" + str(type(e)))
-        return None