commands: use send_apdu_checksw() in method read_record

At the moment the non checking send_apdu() method is used when records
are read. Lets use read_record_checksw so that we get an exception in
case there is a problem to read the specified record.

Change-Id: I9fc411e1b12e8d9fd89b9964209808c0706011bd
diff --git a/pySim/commands.py b/pySim/commands.py
index cea330e..674e184 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -228,7 +228,7 @@
 		r = self.select_path(ef)
 		rec_length = self.__record_len(r)
 		pdu = self.cla_byte + 'b2%02x04%02x' % (rec_no, rec_length)
-		return self._tp.send_apdu(pdu)
+		return self._tp.send_apdu_checksw(pdu)
 
 	def update_record(self, ef, rec_no:int, data:str, force_len:bool=False, verify:bool=False,
 					  conserve:bool=False):