utils: catch exceptions during reader initalitation

Failed reader initializations happen frome time to time, mostly because
of messed up commandline arguments. This results in ugly crashes very
often. Lets control this a bit by catching the exception string and
print it.

Change-Id: I313017355da01bbef7c3d3f1899555aadb509319

pySim-prog.py

@@ -720,6 +720,8 @@ 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

@@ -82,6 +82,8 @@ 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/utils.py

@@ -607,6 +607,7 @@ def init_reader(opts):
 	"""
 	Init card reader driver
 	"""
+	try:
 		if opts.pcsc_dev is not None:
 			print("Using PC/SC reader interface")
 			from pySim.transport.pcsc import PcscSimLink
@@ -623,8 +624,11 @@ def init_reader(opts):
 			print("Using serial reader interface")
 			from pySim.transport.serial import SerialSimLink
 			sl = SerialSimLink(device=opts.device, baudrate=opts.baudrate)
-
 		return sl
+	except Exception as e:
+		print("Card reader initialization failed with exception:\n" + str(e))
+		return None
+
 
 def enc_ePDGSelection(hexstr, mcc, mnc, epdg_priority='0001', epdg_fqdn_format='00'):
 	"""