[BUGFIX]API-45 and remove streeor\perror

Change-Id: Ibee2e67ffad4c8c2fb2c50d6a3dcb7afedea4281
diff --git a/lib/liblynq-sim/src/lynq_sim.cpp b/lib/liblynq-sim/src/lynq_sim.cpp
index 85a8c5b..2503739 100755
--- a/lib/liblynq-sim/src/lynq_sim.cpp
+++ b/lib/liblynq-sim/src/lynq_sim.cpp
@@ -396,6 +396,8 @@
         return ret;
     if(!strlen(new_pin))
         return ret;
+    if(!strlen(old_pin))
+        return ret;
     int send_num = 0;
     int recv_num = 0;
     char res_data[MAX_LEN] = {0};