Fix code warning.

Change-Id: Ib11fb49f528d3688351ae349d5b4e307c28b3967
diff --git a/mbtk/mbtk_servicesd/instance_monitor_service.c b/mbtk/mbtk_servicesd/instance_monitor_service.c
index 2557304..a814bd6 100755
--- a/mbtk/mbtk_servicesd/instance_monitor_service.c
+++ b/mbtk/mbtk_servicesd/instance_monitor_service.c
@@ -31,7 +31,7 @@
 static void program_start(instance_info_t *info)
 {
     LOGD("Will start program : %s", info->ins_name);
-    system(info->ins_cmd);
+    mbtk_system(info->ins_cmd);
 }
 
 static int pidof(const char *program)