cards: return SW in method update_plmnsel() of class Card

The method update_plmnsel() does not return the status word yet, which
causes pysim-prog.py to print an error message that does not influence
the functionality but does not look nice.

- preserve the status word that is returned with update_binary() and
  return it properly like the other methods do.

Change-Id: I54e8e165f87365e8162b36d24efc8f0db62b66da
Related: SYS#4245

pySim/cards.py

@@ -87,7 +87,8 @@ class Card(object):
 	        data = self._scc.read_binary(EF['PLMNsel'], length=None, offset=0)
                 size = len(data[0])/2
 		hplmn = enc_plmn(mcc, mnc)
-		self._scc.update_binary(EF['PLMNsel'], hplmn + 'ff' * (size-3))
+		data, sw = self._scc.update_binary(EF['PLMNsel'], hplmn + 'ff' * (size-3))
+		return sw
 
 	def update_smsp(self, smsp):
 		data, sw = self._scc.update_record(EF['SMSP'], 1, rpad(smsp, 84))