fix: execve params

starter/ns_exec.c

@@ -71,7 +71,7 @@ static int nsrun(void* arg) {
     char* env[]={
         "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
         "PWD=/",
-        "NULL",
+        NULL,
     };
     if (execve(cmd,argv,env) == -1) die("failed to exec,%m");
     return 1;