Fix code warning.

Change-Id: Ib11fb49f528d3688351ae349d5b4e307c28b3967
diff --git a/mbtk/test/libmbtk_wifi/mbtk_wifi_test.c b/mbtk/test/libmbtk_wifi/mbtk_wifi_test.c
old mode 100644
new mode 100755
index 1842b2a..bc5a5a7
--- a/mbtk/test/libmbtk_wifi/mbtk_wifi_test.c
+++ b/mbtk/test/libmbtk_wifi/mbtk_wifi_test.c
@@ -2,8 +2,9 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
-
+#include "mbtk_utils.h"
 #define STA_BUF_SIZE 2048
 
 
@@ -71,10 +72,10 @@
         printf("Parse cmd fail.\n");
     }
 
-    system("udhcpc -i wlan0");
+    mbtk_system("udhcpc -i wlan0");
 
-    
-    
+
+
     return 0;
 }