transport/bt_rsap.py: fix unknown variable in reset_card()

Change-Id: I50f0f8d9ad30994c4d9693157dfa1a0c52753178
diff --git a/pySim/transport/bt_rsap.py b/pySim/transport/bt_rsap.py
index 861432a..9d175dc 100644
--- a/pySim/transport/bt_rsap.py
+++ b/pySim/transport/bt_rsap.py
@@ -305,7 +305,7 @@
         self.connected = False
 
     def reset_card(self):
-        if self._connected:
+        if self.connected:
             self.send_sap_message("RESET_SIM_REQ")
             msg_name, param_list = self._recv_sap_response('RESET_SIM_RESP')
             connection_status = next(